Polynucleotides and polypeptides involved in plant fiber development and methods of using same

ABSTRACT

Isolated polynucleotides are provided. Each of the isolated polynucleotides comprise a nucleic acid sequence encoding a polypeptide having an amino acid sequence at least 80% homologous to SEQ ID NOs:130-258 and 536-791, wherein the polypeptide is capable of regulating cotton fiber development. Also provided are methods of using such polynucleotides for improving fiber quality and/or yield of a fiber producing plant, as well as methods of using such polynucleotides for producing plants having increased biomass/vigor/yield.

RELATED APPLICATIONS

This application is a division of U.S. patent application Ser. No.13/418,422, filed on Mar. 13, 2012, which is a continuation of U.S.patent application Ser. No. 12/448,359 filed on Jun. 18, 2009, now U.S.Pat. No. 8,168,857, which is a National Phase of PCT Patent ApplicationNo. PCT/IL2007/001590 having International Filing Date of Dec. 20, 2007,which claims the benefit of priority of U.S. Provisional PatentApplication No. 60/875,804 filed on Dec. 20, 2006. The contents of theabove Applications are all incorporated herein by reference.

SEQUENCE LISTING STATEMENT

The ASCII file, entitled 69140SequenceListing.txt, created on Feb. 12,2017, comprising 1,554,112 bytes, submitted concurrently with the filingof this application is incorporated herein by reference.

FIELD AND BACKGROUND OF THE INVENTION

The invention, in some embodiments thereof, relates to polynucleotidesand polypeptides involved in plant-fiber development and methods ofusing same.

Cotton and cotton by-products provide raw materials that are used toproduce a wealth of consumer-based products in addition to textilesincluding cotton foodstuffs, livestock feed, fertilizer and paper. Theproduction, marketing, consumption and trade of cotton-based productsgenerate an excess of $100 billion annually in the U.S. alone, makingcotton the number one value-added crop. In spite of the growth ofsynthetic fibers in the last 50 years, cotton still accounts forapproximately 50% of the world's textile fiber. Even though 90% ofcotton's value as a crop resides in the fiber (lint), yield and fiberquality has declined, especially over the last decade. This decline hasbeen attributed to general erosion in genetic diversity of cottonvarieties, and an increased vulnerability of the crop to environmentalconditions.

Cotton fibers can be obtained from many varieties of cotton with a rangeof characteristics for various applications. Cotton fibers may becharacterized according to a variety of properties, some of which areconsidered highly desirable within the textile industry for theproduction of increasingly high quality products and optimalexploitation of modern spinning technologies. Commercially desirableproperties include length, length uniformity, fineness, maturity ratio,decreased fuzz fiber production, micronaire, bundle strength, and singlefiber strength. Much effort has been put into the improvement of thecharacteristics of cotton fibers mainly focusing on fiber length andfiber fineness. In particular, there is a great demand for cotton fibersof specific lengths.

Several approaches can be used to improve the characteristics or yieldof cotton fibers. Variety improvement of cultivated cotton plants hasbeen performed by cross breeding. However, breeding is relatively slowand inefficient, and the degree of variability which can be achieved islimited to the existing genetic diversity. In addition, plants can betreated with hormones such as auxin, gibberellin, cytokinin, ethylene orbrassinolide [see e.g. U.S. Pat. No. 5,880,110]. However, no measurableeffect of the hormones has been documented, making practical use ofthese hormones on a large scale highly unlikely. Alternatively, varietyimprovement can be achieved by genetic engineering. In recent years, aremarkable progress has been made in plant genetic engineering with thesuccessful variety improvement of commercially important crop plantssuch as cotton, soybean, corn, and canola. The broad acceptance ofgenetically engineered cotton in the leading producing countries make itan attractive candidate for genetic engineering for improvement of fiberyield and/or quality. For example, introducing a gene coding for aninsecticidal protein toxin produced Bacillus thuringiensis (BT) into acotton plant has improved insect resistance. In addition, cotton plantswith improved herbicide (Glyphosate) resistance have been geneticallyengineered by the introduction of a gene coding for5-enol-pyruvil-shikimic acid 3-phosphate synthetase.

A cotton fiber is composed of a single cell that has differentiated froman epidermal cell of the seed coat, developing through fourchronological stages, i.e., initiation, elongation, secondary cell wallthickening and maturation stages. The elongation of a cotton fibercommences in the epidermal cell of the ovule immediately followingflowering, after which the cotton fiber rapidly elongates forapproximately 21 days. Fiber elongation is then terminated, and asecondary cell wall is formed and grows through maturation to become amature cotton fiber.

Little is known about the genetic control of cotton fiber initiation andelongation. Since both cotton fibers and Arabidopsis trichomes aredeveloped from single epidermal cells it was suggested that they bothshare similar genetic regulation (Reviewed at Wagner G. J. et. al.2004). In Arabidopsis, a large number of studies have revealed extensiveinformation on the genetic mechanisms regulating trichome initiation andelongation. Several studies demonstrated the similarities betweentrichome and fiber by showing that cotton fiber specific promotersconfer trichome specific expression in arabidopsis and tobacco plants(Kim and Triplett, 2001; Hsu et. al. 1999; Liu et. al. 2000, Wang et al.2004). Most of the research that studies fiber development usesarabidopsis trichome as a model system to identify cotton genes in asmall scale manner (Kim and Triplett, 2001; Wang et al. 2004).

Several candidate genes associated with the elongation and formation ofcotton fibers have been identified. For example, five genes from cottonplants which are specifically expressed at the cotton fiber elongationstage were identified by differential screening and display methods[U.S. Pat. Nos. 5,880,100 and 5,932,713, 6,225,536 and 6,166,294].

WO0245485 describes methods and means to modulate fiber quality infiber-producing plants, such as cotton, by modulating sucrose synthase(a sugar important for cell wall synthesis) activity and/or expressionin such plants.

U.S. Pat. No. 6,472,588 and WO0117333 provide methods of increasing thequality of cotton fiber (e.g., strength, length, fiber maturity ratio,immature fiber content, fiber uniformity or micronaire) by transforminga cotton plant with a DNA encoding sucrose phosphate synthase.

WO9508914 discloses a fiber producing plant comprising in its genome aheterologous genetic construct which includes a fiber-specific promoterand a coding sequence encoding a plant peroxidase, such as a cottonperoxidase.

WO9626639 provides a method utilizing an ovary specific promotersequence to express plant growth modifying hormones in cotton ovuletissue. The method permits the modification of the characteristics ofboll set in cotton plants and provides a mechanism for altering fiberquality characteristics such as fiber dimension and strength.

U.S. Pat. Nos. 5,981,834, 5,597,718, 5,620,882, 5,521,708 and 5,495,070disclose a method of genetically engineering a fiber-producing plant andthe identification of cDNA clones useful for identifying fiber genes incotton.

U.S. patent applications 2002049999 and 2003074697 disclose cottonplants of the genus Gossypium expressing endoxyloglucan transferase,catalase or peroxidase with improved cotton fiber characteristics.

WO 01/40250 provides a method of improving cotton fiber quality bymodulating transcription factor gene expression.

WO 96/40924 provides novel DNA constructs which may be used as molecularprobes or alternatively inserted into a plant host to modifytranscription of a DNA sequence-of-interest during various stages ofcotton fiber development.

EP0834566 discloses a gene which controls the fiber formation mechanismin a cotton plant.

Validation of genes which improve cotton fiber yield and quality in vivorequires a reliable model system for cotton fiber development. Models inother plant platforms, such as trichome cells and root hairs, are widelyaccepted for cotton fiber development. However measuring changes ingrowth rate, cell length and thickness is not easy because of the smallsize, difficult access to and lack of uniformity in sizes. The presentinventors have analyzed tomato seed hairs for their possible use as amodel tissue for cotton fiber development (WO2005/121364 which isincorporated herein by reference) and demonstrated a high correlationbetween tomato seed hair and cotton fiber.

The generation of stably transformed transgenic plants to assess genefunction is a lengthy manipulative process. As an alternative, foreigngene expression in plants is often performed using transienttransformation of cells or tissues. Agrobacterium mediated transientgene expression (agroinfiltration) in plant leaves has become thefavorite choice in many gene functional analyses (Kapila et al., 1997;Yang et al., 2000; Goodin et al., 2002). There are existing protocolsfor transient gene expression in tissue-culture grown cotton fibers[such as Kim H J, et al., 2001]. Orzaez D., et al. 2006, developed anagroinfiltration-based system (agroinjection), which allows transientexpression of foreign genes directly in tomato fruit tissues.

SUMMARY OF THE INVENTION

According to an aspect of some embodiments of the invention there isprovided an isolated polynucleotide comprising a nucleic acid sequenceencoding a polypeptide having an amino acid sequence at least 80%homologous to an amino acid sequence selected from the group consistingof SEQ ID NOs:130, 141, 131, 146, 139, 140, 137, 133, 136, 135, 134,132, 138, 142, 143, 144, 145, 147-258 and 536-791, wherein thepolypeptide is capable of regulating fiber development.

According to an aspect of some embodiments of the invention there isprovided an isolated polypeptide comprising an amino acid sequence atleast 80% homologous to an amino acid sequence selected from the groupconsisting of SEQ ID NOs: 130, 141, 131, 146, 139, 140, 137, 133, 136,135, 134, 132, 138, 142, 143, 144, 145, 147-258 and 536-791, wherein thepolypeptide is capable of regulating fiber development.

According to an aspect of some embodiments of the invention there isprovided an isolated polynucleotide comprising a nucleic acid sequenceat least 95% identical to SEQ ID NO: 851, 848, 857, or 854, wherein thenucleic acid sequence is capable of regulating an expression of aheterologous polynucleotide sequence operably linked thereto.

According to an aspect of some embodiments of the invention there isprovided a nucleic acid construct comprising the isolatedpolynucleotide.

According to an aspect of some embodiments of the invention there isprovided a nucleic acid construct comprising the isolated polynucleotideand a heterologous nucleic acid sequence operably attached thereto.

According to an aspect of some embodiments of the invention there isprovided a transgenic cell comprising the isolated polynucleotide.

According to an aspect of some embodiments of the invention there isprovided a transgenic cell exogenously expressing the isolatedpolypeptide.

According to an aspect of some embodiments of the invention there isprovided a transgenic plant comprising the isolated polynucleotide.

According to an aspect of some embodiments of the invention there isprovided a transgenic plant exogenously expressing the isolatedpolypeptide.

According to an aspect of some embodiments of the invention there isprovided a method of increasing a biomass of a plant, the methodcomprising exogenously expressing the isolated polypeptide in the plant,thereby increasing the biomass of the plant.

According to an aspect of some embodiments of the invention there isprovided a method of increasing a vigor of a plant, the methodcomprising exogenously expressing the isolated polypeptide in the plant,thereby increasing the vigor of the plant.

According to an aspect of some embodiments of the invention there isprovided a method of increasing a yield of a plant, the methodcomprising exogenously expressing the isolated polypeptide in the plant,thereby increasing the yield of the plant.

According to an aspect of some embodiments of the invention there isprovided a method of increasing a tolerance of a plant to abioticstress, the method comprising exogenously expressing the isolatedpolypeptide in the plant, thereby increasing the tolerance of the plantto abiotic stress.

According to an aspect of some embodiments of the invention there isprovided a method of improving fiber quality and/or yield of a fiberproducing plant, the method comprising exogenously expressing theisolated polypeptide in the fiber producing plant, thereby improving thequality and/or yield of the fiber producing plant.

According to an aspect of some embodiments of the invention there isprovided a method of increasing a biomass of a plant, the methodcomprising expressing the nucleic acid construct in the plant, therebyincreasing the biomass of the plant.

According to an aspect of some embodiments of the invention there isprovided a method of increasing a vigor of a plant, the methodcomprising expressing the nucleic acid construct in the plant, therebyincreasing the vigor of the plant.

According to an aspect of some embodiments of the invention there isprovided a method of increasing a yield of a plant, the methodcomprising expressing the nucleic acid construct in the plant, therebyincreasing the yield of the plant.

According to an aspect of some embodiments of the invention there isprovided a method of producing cotton fibers, the method comprising: (a)generating a transgenic cotton plant exogenously expressing the isolatedpolypeptide; and (b) harvesting the fibers of the transgenic cottonplant, thereby producing the cotton fibers.

According to an aspect of some embodiments of the invention there isprovided a nucleic acid construct comprising: (i) a first polynucleotidesequence which comprises a reporter gene operably linked to afiber-specific promoter; and (ii) a second polynucleotide sequence whichcomprises a heterologous nucleic acid sequence encoding apolypeptide-of-interest operably linked to a promoter.

According to an aspect of some embodiments of the invention there isprovided a nucleic acid construct system comprising: (i) a first nucleicacid construct which comprises a first polynucleotide sequencecomprising a reporter gene operably linked to a fiber-specific promoter;and (ii) a second nucleic acid construct which comprises a secondpolynucleotide sequence comprising a heterologous nucleic acid sequenceencoding a polypeptide-of-interest operably linked to a promoter.

According to an aspect of some embodiments of the invention there isprovided a method of expressing a polypeptide-of-interest in a plant,comprising administering to the plant the nucleic acid construct or thenucleic acid construct system, thereby expressing thepolypeptide-of-interest in the plant.

According to an aspect of some embodiments of the invention there isprovided a method of expressing a polypeptide-of-interest in a cottonplant, comprising injecting to a cotton ball of the cotton plant anucleic acid construct which comprises a nucleic acid sequence encodingthe polypeptide-of-interest, there by expressing thepolypeptide-of-interest in the cotton plant.

According to an aspect of some embodiments of the invention there isprovided a cell comprising the nucleic acid construct or the nucleicacid construct system.

According to some embodiments of the invention, the nucleic acidsequence is selected from the group consisting of SEQ ID NOs:1, 12, 2,17, 10, 11, 8, 4, 7, 6, 5, 3, 9, 13, 14, 15, 16, 18-129 and 259-535.

According to some embodiments of the invention, the polypeptide isselected from the group consisting of SEQ ID NOs: 130, 141, 131, 146,139, 140, 137, 133, 136, 135, 134, 132, 138, 142, 143, 144, 145, 147-258and 536-791.

According to some embodiments of the invention, the isolatedpolynucleotide is as set forth by SEQ ID NO: 851, 848, 857, or 854.

According to some embodiments of the invention, the nucleic acidsequence is shorter than 1800 bp.

According to some embodiments of the invention, the fiber comprises acotton fiber.

According to some embodiments of the invention, the nucleic acidconstruct further comprises at least one cis-acting regulatory elementoperably linked to the isolated polynucleotide.

According to some embodiments of the invention, expressing is effectedat a root tip of the plant.

According to some embodiments of the invention, the quality of the fiberproducing plant comprises at least one parameter selected from the groupconsisting of fiber length, fiber strength, fiber weight per unitlength, maturity ratio, uniformity and micronaire.

According to some embodiments of the invention, the fiber producingplant is selected from the group consisting of cotton, silk cotton tree,desert willow, creosote bush, winterfat, balsa, ramie, kenaf, hemp,roselle, jute, sisal abaca and flax.

According to some embodiments of the invention, the fiber developmentcomprises fiber formation.

According to some embodiments of the invention, the fiber developmentcomprises fiber elongation.

According to some embodiments of the invention, the plant is a cottonplant. According to some embodiments of the invention, administering iseffected by injecting the nucleic acid construct or the nucleic acidconstruct system to a cotton ball of the cotton plant.

According to some embodiments of the invention, the nucleic acidconstruct is comprised in agrobacteria.

According to some embodiments of the invention, expressing is effectedin an ovule cell of the cotton plant.

According to some embodiments of the invention, thepolypeptide-of-interest regulates fiber development.

Unless otherwise defined, all technical and/or scientific terms usedherein have the same meaning as commonly understood by one of ordinaryskill in the art to which the invention pertains. Although methods andmaterials similar or equivalent to those described herein can be used inthe practice or testing of embodiments of the invention, exemplarymethods and/or materials are described below. In case of conflict, thepatent specification, including definitions, will control. In addition,the materials, methods, and examples are illustrative only and are notintended to be necessarily limiting.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The patent or application file contains at least one drawing executed incolor. Copies of this patent or patent application publication withcolor drawings will be provided by the Office upon request and paymentof the necessary fee.

Some embodiments of the invention are herein described, by way ofexample only, with reference to the accompanying drawings. With specificreference now to the drawings in detail, it is stressed that theparticulars shown are by way of example and for purposes of illustrativediscussion of embodiments of the invention. In this regard, thedescription taken with the drawings makes apparent to those skilled inthe art how embodiments of the invention may be practiced.

In the drawings:

FIG. 1 is a schematic illustration of the pGI binary plasmid used forexpressing the isolated polynucleotide sequences of the invention underthe control of the 35S promoter. RB—T-DNA right border; LB—T-DNA leftborder; H—HindIII restriction enzyme; X—XbaI restriction enzyme; B—BamHIrestriction enzyme; S—SalI restriction enzyme; Sm—SmaI restrictionenzyme; R-I—EcoRI restriction enzyme; Sc—SacI/SstI/Ecl136II;(numbers)—Length in base-pairs; NOS pro=nopaline synthase promoter;NPT-II=neomycin phosphotransferase gene; NOS ter=nopaline synthaseterminator; Poly-A signal (polyadenylation signal); GUSintron—the GUSreporter gene (coding sequence and intron) The isolated polynucleotidesequences of the invention were cloned into the vector while replacingthe GUSintron reporter gene.

FIGS. 2a-2d are bar graph depicting the expression profile of selectedfiber development genes at various developmental stages measured in dayspost anthesis (DPA) and tissues. FIG. 2a —CT4 (SEQ ID NO: 842); FIG. 2b—CT74 (SEQ ID NO: 843); FIG. 2c —CT11 (SEQ ID NO:844); FIG. 2d —CT9 (SEQID NO:857). The developmental stages and tissues were as follows: (a) −2DPA; (b) 0-1 DPA; (c) 2-3 DPA; (d) 4-5 DPA; (e) 6-8 DPA; (f) 9-11 DPA;(g) 12-14 DPA; (h) 15-17 DPA; (i) 18-20 DPA; (j) young leaves: (k) youngstems; (1) young roots; (m) leaves; (n) stems; (o) sepals; (p) petals;(q) stamen (G. hirsutum var. Acala) plants. Relative amounts of mRNA arepresented in all examined tissues. The y-axis represents the expressionlevel normalized against three different housekeeping genes;

FIGS. 3a-3f are photomicrographs depicting fiber-specific promoterevaluation in Arabidopsis. Expression of GUS in leafs (FIGS. 3a-3c ) androots (FIGS. 3d-3f ) under regulation of 35S promoter (SEQ ID NO: 841)(FIGS. 3a and 3d ), CT4 promoter (SEQ ID NO:848) (FIGS. 3b and 3e ) andCT74 promoter (SEQ ID NO:851) (FIGS. 3c and 3f ). Note the high stainingintensity (corresponding to high expression level) of GUS in the leafsof Arabidopsis plants under the CT4 (FIG. 3b ) or the CT74 (FIG. 3c )promoters;

FIGS. 4a-4c are photomicrographs depicting promoter detection in cottonballs using a specific embodiment of the transient assay describedherein, Agroinjection of GUS under regulation of CT2 or 35S promoters.FIG. 4a —CT2::GUS at 3 DPA; FIG. 4 b—35S::GUS at 3DPA; FIG. 4 c—35S::GUSat 8 DPA;

FIGS. 5a-5c are photomicrographs depicting overexpression of CT20 andexpansin in cis to GFP reporter gene by transient transfection of cottonballs at 4 DPA development fibers. For control, the agroinjection ofCT2::GFP was used; FIG. 5a —CT2::GFP (control); FIG. 5b—CT2::GFP+35S::CT20 (by transient transfection of the binary vectordepicted in FIG. 7); FIG. 5c —CT2::GFP+35S::Expansin;

FIG. 6 is a schematic illustration depicting an exemplary binary vectorof the invention [designated pGI(CT2 promoter)+CT82(35S promoter)], inwhich the CT82 ORF (SEQ ID NO:890) is under the transcriptional controlof the constitutive 35S promoter (SEQ ID NO:841) and the GUSIntron (SEQID NO:872) is under the transcriptional control of the CT2 promoter (SEQID NO:873). NOS pro=nopaline synthase promoter; NPT-II=neomycinphosphotransferase gene; NOS ter=nopaline synthase terminator;

FIG. 7 is a schematic illustration depicting an exemplary binary vectorof the invention [designated pCT20-FGFP(CT2prom)], in which the GFP openreading frame (ORF) (SEQ ID NO:871) is under the transcriptional controlof the CT2 promoter (SEQ ID NO:873) and the CT20 ORF (SEQ ID NO:881) isunder the transcriptional control of the constitutive 35S promoter (SEQID NO:841). NOS pro=nopaline synthase promoter; NPT-II=neomycinphosphotransferase gene; NOS ter=nopaline synthase terminator;

DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION

The invention, in some embodiments thereof, relates to polynucleotidesand polypeptides involved in plant-fiber development and methods ofusing same for improving fiber quality and/or yield/biomass/vigor of aplant, and in an exemplary embodiment a fiber-producing plant.

Before explaining at least one embodiment of the invention in detail, itis to be understood that the invention is not necessarily limited in itsapplication to the details set forth in the following description orexemplified by the Examples. The invention is capable of otherembodiments or of being practiced or carried out in various ways.

While reducing the invention to practice, the present inventors haveidentified polynucleotides and polypeptides encoded thereby which areinvolved in fiber development and which can be used to increase fiberquality and/or yield and plant biomass.

Thus, as described in the Examples section which follows, the presentinventors have devised a novel computational approach combined withfiber related expression profile data generated using cottonoligonucleotide microarray and quantitative RT-PCR to identify geneswhich play a role in fiber development. Genes which are expressed duringfiber initiation and elongation, in elongated tissues such as root tips,xylem and/or under etiolating conditions such as abiotic stress (e.g.,drought) were identified (Example 1 of the Examples section whichfollows) and their expression profile was determined in a variety ofcotton plants at several fiber developmental stages (Examples 2, 3 and 4of the Example section which follows). Genes in which the expressionprofile correlated with fiber development were selected (polynucleotidesSEQ ID NOs:1-129; polypeptides SEQ ID NOs:130-258; Table 7, Example 4 ofthe Examples section which follows), as well as homologous polypeptides(SEQ ID NOs:536-791) from other plant species (Table 8, Example 4 of theExamples section which follows). As is further described in Examples 5,6 and 7 of the Examples section which follows, exogenous expression ofbinary nucleic acid vectors harboring selected fiber development genes(e.g., SEQ ID NOs:1-17, 22 and 37) under the transcriptional control ofa constitutive promoter (Cauliflower Mosaic Virus 35S promoter) intomato plants resulted in an overall effect on the length of tomato seedhair. In addition, promoter sequences of genes involved in fiberdevelopment were isolated (SEQ ID NOs:851, 848, 857, or 854; Example 8of the Examples section which follows), cloned in binary vectorsupstream of a reported gene (GUS) (Example 9 of the Examples section)and exogenously expressed in tomato plants (Example 10 of the Examplessection). These expression studies demonstrated the identification ofpromoter sequences which are active during initiation (CT4 promoter; SEQID NO:848) or elongation (CT9 and CT74 promoters; SEQ ID NOs:857 and851, respectively) of fiber development (Example 10 of the Examplessection). Altogether, these results demonstrate that the isolatedpolynucleotides (e.g., SEQ ID NOs:1-129 and 259-535) and polypeptides(e.g., SEQ ID NOs:130-258 and 536-791) of the invention, as well as theisolated fiber development promoters (e.g., SEQ ID NOs:851, 848, 857, or854) can be used to improve fiber quality and/or yield of a fiberproducing plant and increase the biomass/vigor/yield as well asresistance or tolerance to abiotic stress of plants altogether.

Thus, according to one aspect of the invention, there is provided anisolated polynucleotide comprising a nucleic acid sequence encoding apolypeptide having an amino acid sequence at least 80% homologous to anamino acid sequence selected from the group consisting of SEQ IDNOs:130, 141, 131, 146, 139, 140, 137, 133, 136, 135, 134, 132, 138,142, 143, 144, 145, 147-258 and 536-791, wherein the polypeptide iscapable of regulating fiber development.

As used herein the phrase “fiber producing plant” refers to plants thatshare the common feature of having an elongated shape and abundantcellulose in thick cell walls, typically termed as secondary walls. Suchwalls may or may not be lignified, and the protoplast of such cells mayor may be viable at maturity. Such fibers have many industrial uses, forexample in lumber and manufactured wood products, paper, textiles,sacking and boxing material, cordage, brushes and brooms, filling andstuffing, caulking, reinforcement of other materials, and manufacture ofcellulose derivatives.

The term “fiber” is usually inclusive of thick-walled conducting cellssuch as vessels and tracheids and to fibrillar aggregates of manyindividual fiber cells. Hence, the term “fiber” refers to (a)thick-walled conducting and non-conducting cells of the xylem; (b)fibers of extraxylary origin, including those from phloem, bark, groundtissue, and epidermis; and (c) fibers from stems, leaves, roots, seeds,and flowers or inflorescences (such as those of Sorghum vulgare used inthe manufacture of brushes and brooms).

Example of fiber producing plants, include, but are not limited to,agricultural crops such as cotton, silk cotton tree (Kapok, Ceibapentandra), desert willow, creosote bush, winterfat, balsa, kenaf,roselle, jute, sisal abaca, flax, corn, sugar cane, hemp, ramie, kapok,coir, bamboo, spanish moss and Agave spp. (e.g. sisal).

According to an embodiment of this aspect of the invention the fiberproducing plant is cotton.

As used herein the term “cotton” refers to a wild-type, a cultivatedvariety (e.g., hybrid) or a transgenic cotton (Gossypium) plant.

The phrase “cotton fiber development” refers to the development of thehair of the cotton seed.

As used herein the term “development” when used in context of fibers(e.g., cotton fibers) refers to initiation of the fiber (formation offiber) and/or elongation thereof, as well as to the fiber secondary cellwall thickening and maturation.

Thus, the invention encompasses polynucleotides identified using thepresent methodology and their encoded polypeptide as well aspolynucleotides encoding functional equivalents of the polypeptidesidentified herein (i.e., polypeptides which are capable of regulatingfiber development, as can be determined according to the assaysdescribed in the Examples section which follows). Such functionalequivalents can be at least about 70%, at least about 75%, at leastabout 80%, at least about 81%, at least about 82%, at least about 83%,at least about 84%, at least about 85%, at least about 86%, at leastabout 87%, at least about 88%, at least about 89%, at least about 90%,at least about 91%, at least about 92%, at least about 93%, at leastabout 94%, at least about 95%, e.g., 96%, 97%, 98%, 99% or 100%homologous to an amino acid sequence selected from the group consistingof SEQ ID NO: 130, 141, 131, 146, 139, 140, 137, 133, 136, 135, 134,132, 138, 142, 143, 144, 145, 147-258 and 536-791.

Homology of an amino acid sequence (e.g., percent homology) can bedetermined using any homology comparison software, including forexample, the BlastP software of the National Center of BiotechnologyInformation (NCBI) such as by using default parameters.

Polynucleotides encoding the functional equivalents can be at leastabout 70%, at least about 75%, at least about 80%, at least about 81%,at least about 82%, at least about 83%, at least about 84%, at leastabout 85%, at least about 86%, at least about 87%, at least about 88%,at least about 89%, at least about 90%, at least about 91%, at leastabout 92%, at least about 93%, at least about 94%, at least about 95%,at least about 96%, at least about 97%, at least about 98%, at leastabout 99%, e.g., 100% identical or homologous to a nucleic acid sequenceselected from the group consisting of SEQ ID NO:1, 12, 2, 17, 10, 11, 8,4, 7, 6, 5, 3, 9, 13, 14, 15, 16, 18-129 and 259-535.

Identity of a nucleic acid sequence (e.g., percent homology) can bedetermined using any homology comparison software, including forexample, the BlastN software of the National Center of BiotechnologyInformation (NCBI) such as by using default parameters.

As used herein the phrase “an isolated polynucleotide” refers to asingle or double stranded nucleic acid sequences which is isolated andprovided in the form of an RNA sequence, a complementary polynucleotidesequence (cDNA), a genomic polynucleotide sequence and/or a compositepolynucleotide sequences (e.g., a combination of the above).

As used herein the phrase “complementary polynucleotide sequence” refersto a sequence, which results from reverse transcription of messenger RNAusing a reverse transcriptase or any other RNA dependent DNA polymerase.Such a sequence can be subsequently amplified in vivo or in vitro usinga DNA dependent DNA polymerase.

As used herein the phrase “genomic polynucleotide sequence” refers to asequence derived (isolated) from a chromosome and thus it represents acontiguous portion of a chromosome.

As used herein the phrase “composite polynucleotide sequence” refers toa sequence, which is at least partially complementary and at leastpartially genomic. A composite sequence can include some exonalsequences required to encode the polypeptide of the invention, as wellas some intronic sequences interposing therebetween. The intronicsequences can be of any source, including of other genes, and typicallywill include conserved splicing signal sequences. Such intronicsequences may further include cis acting expression regulatory elements.

According to an embodiment of this aspect of the invention, the nucleicacid sequence is as set forth in SEQ ID NO:1, 12, 2, 17, 10, 11, 8, 4,7, 6, 5, 3, 9, 13, 14, 15, 16, 18-129, 259-534 or 535.

According to an embodiment of this aspect of the invention, the isolatedpolynucleotide is as set forth in SEQ ID NO:1, 12, 2, 17, 10, 11, 8, 4,7, 6, 5, 3, 9, 13, 14, 15, 16, 18-129, 259-534 or 535.

According to an embodiment of this aspect of the invention, the aminoacid sequence is as set forth in SEQ ID NO:130, 141, 131, 146, 139, 140,137, 133, 136, 135, 134, 132, 138, 142, 143, 144, 145, 147-258, 536-790or 791.

According to an embodiment of this aspect of the invention, thepolypeptide is as set forth in SEQ ID NO:130, 141, 131, 146, 139, 140,137, 133, 136, 135, 134, 132, 138, 142, 143, 144, 145, 147-258, 536-790or 791.

The isolated polynucleotides of this aspect of the invention can be alsoqualified using a hybridization assay by incubating the isolatedpolynucleotides described above in the presence of an oligonucleotideprobe or primer under moderate to stringent hybridization conditions.

Moderate to stringent hybridization conditions are characterized by ahybridization solution such as containing 10% dextrane sulfate, 1 MNaCl, 1% SDS and 5×10⁶ cpm ³²P labeled probe, at 65° C., with a finalwash solution of 0.2×SSC and 0.1% SDS and final wash at 65° C. andwhereas moderate hybridization is effected using a hybridizationsolution containing 10% dextrane sulfate, 1 M NaCl, 1% SDS and 5×10⁶ cpm³²P labeled probe, at 65° C., with a final wash solution of 1×SSC and0.1% SDS and final wash at 50° C.

Nucleic acid sequences encoding the polypeptides of the invention may beoptimized for plant expression. Examples of such sequence modificationsinclude, but are not limited to, an altered G/C content to more closelyapproach that typically found in the plant species of interest, and theremoval of codons atypically found in the plant species commonlyreferred to as codon optimization.

The phrase “codon optimization” refers to the selection of appropriateDNA nucleotides for use within a structural gene or fragment thereofthat approaches codon usage within the plant of interest. Therefore, anoptimized gene or nucleic acid sequence refers to a gene in which thenucleotide sequence of a native or naturally occurring gene has beenmodified in order to utilize statistically-preferred orstatistically-favored codons within the plant. The nucleotide sequencetypically is examined at the DNA level and the coding region optimizedfor expression in the plant species determined using any suitableprocedure, for example as described in Sardana et al. (1996, Plant CellReports 15:677-681). In this method, the standard deviation of codonusage, a measure of codon usage bias, may be calculated by first findingthe squared proportional deviation of usage of each codon of the nativegene relative to that of highly expressed plant genes, followed by acalculation of the average squared deviation. The formula used is: 1SDCU=n=1 N [(Xn−Yn)/Yn]2/N, where Xn refers to the frequency of usage ofcodon n in highly expressed plant genes, where Yn to the frequency ofusage of codon n in the gene of interest and N refers to the totalnumber of codons in the gene of interest. A table of codon usage fromhighly expressed genes of dicotyledonous plants is compiled using thedata of Murray et al. (1989, Nuc Acids Res. 17:477-498).

One method of optimizing the nucleic acid sequence in accordance withthe preferred codon usage for a particular plant cell type is based onthe direct use, without performing any extra statistical calculations,of codon optimization tables such as those provided on-line at the CodonUsage Database through the NIAS (National Institute of AgrobiologicalSciences) DNA bank in Japan(http://www(dot)kazusa(dot)or(dot)jp/codon/). The Codon Usage Databasecontains codon usage tables for a number of different species, with eachcodon usage table having been statistically determined based on the datapresent in Genbank.

By using the above tables to determine the most preferred or mostfavored codons for each amino acid in a particular species (for example,rice), a naturally-occurring nucleotide sequence encoding a protein ofinterest can be codon optimized for that particular plant species. Thisis effected by replacing codons that may have a low statisticalincidence in the particular species genome with corresponding codons, inregard to an amino acid, that are statistically more favored. However,one or more less-favored codons may be selected to delete existingrestriction sites, to create new ones at potentially useful junctions(5′ and 3′ ends to add signal peptide or termination cassettes, internalsites that might be used to cut and splice segments together to producea correct full-length sequence), or to eliminate nucleotide sequencesthat may negatively effect mRNA stability or expression.

The naturally-occurring encoding nucleotide sequence may already, inadvance of any modification, contain a number of codons that correspondto a statistically-favored codon in a particular plant species.Therefore, codon optimization of the native nucleotide sequence maycomprise determining which codons, within the native nucleotidesequence, are not statistically-favored with regards to a particularplant, and modifying these codons in accordance with a codon usage tableof the particular plant to produce a codon optimized derivative. Amodified nucleotide sequence may be fully or partially optimized forplant codon usage provided that the protein encoded by the modifiednucleotide sequence is produced at a level higher than the proteinencoded by the corresponding naturally occurring or native gene.Construction of synthetic genes by altering the codon usage is describedin for example PCT Patent Application 93/07278.

Thus, the invention encompasses nucleic acid sequences describedhereinabove; fragments thereof, sequences hybridizable therewith,sequences homologous thereto, sequences encoding similar polypeptideswith different codon usage, altered sequences characterized bymutations, such as deletion, insertion or substitution of one or morenucleotides, either naturally occurring or man induced, either randomlyor in a targeted fashion.

Since the polynucleotide sequences of the invention encode previouslyunidentified polypeptides, the invention also encompasses novelpolypeptides or portions thereof, which are encoded by the isolatedpolynucleotides and respective nucleic acid fragments thereof describedhereinabove. The amino acid sequences of these novel polypeptides areset forth in SEQ ID NO:130, 141, 131, 146, 139, 140, 137, 133, 136, 135,134, 132, 138, 142, 143, 144, 145, 147-258 and 536-791.

The invention also encompasses homologues of these polypeptides, suchhomologues can be at least about 70%, at least about 75%, at least about80%, at least about 81%, at least about 82%, at least about 83%, atleast about 84%, at least about 85%, at least about 86%, at least about87%, at least about 88%, at least about 89%, at least about 90%, atleast about 91%, at least about 92%, at least about 93%, at least about93%, at least about 94%, at least about 95%, at least about 96%, atleast about 97%, at least about 98%, at least about 99%, homologous toan amino acid sequence selected from the group consisting of SEQ IDNOs:130, 141, 131, 146, 139, 140, 137, 133, 136, 135, 134, 132, 138,142, 143, 144, 145, 147-258 and 536-791.

According to an embodiment of the invention, the isolated polypeptide ofthe invention is selected from the group consisting of SEQ ID NOs:130,141, 131, 146, 139, 140, 137, 133, 136, 135, 134, 132, 138, 142, 143,144, 145, 147-258 and 536-791.

The invention also encompasses fragments of the above describedpolypeptides and polypeptides having mutations, such as deletions,insertions or substitutions of one or more amino acids, either naturallyoccurring or man induced, either randomly or in a targeted fashion.

As mentioned above and described in Examples 8, 9 and 10 of the Examplessection which follows, the present inventors have isolated promotersequences (SEQ ID NOs:851, 848, 857, or 854) of genes involved in cottonfiber development [CT4 (SEQ ID NO:842), CT9 (SEQ ID NO:843), CT11 (SEQID NO:844) and CT74 (SEQ ID NO:845)] and demonstrated their ability todirect an expression of a reporter gene in a plant cell.

Thus, according to another aspect of the invention, there is provided anisolated polynucleotide comprising a nucleic acid sequence at least 90%,at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, atleast 96%, at least 97%, at least 98%, at least 99% identical to SEQ IDNO:851, 848, 857, or 854, wherein the nucleic acid sequence is capableof regulating an expression of a heterologous polynucleotide sequenceoperably linked thereto.

As used herein the phrase “heterologous polynucleotide sequence” refersto a polynucleotide from a different species or from the same speciesbut from a different gene locus as of the isolated polynucleotidesequence (e.g., the promoter sequence).

A heterologous polynucleotide sequence is “operably linked” to aregulatory sequence (e.g., the promoter sequence set forth by SEQ IDNO:851, 848, 857, or 854) if the regulatory sequence is capable ofexerting a regulatory effect on the heterologous polynucleotide sequencelinked thereto. Preferably, the regulatory sequence is positioned 1-500bp upstream of the ATG codon of the heterologous polynucleotidesequence, although it will be appreciated that regulatory sequences canalso exert their effect when positioned elsewhere with respect to thecoding nucleic acid sequence (e.g., within an intron).

According to an embodiment of the invention, the isolated polynucleotidesequence of this aspect of the invention (the promoter sequence)comprises less than about 1800 nucleic acids in length, e.g., less thanabout 1500 nucleic acids in length.

According to an embodiment of this aspect of the invention, the isolatedpolynucleotide sequence comprises a nucleic acid sequence as set forthby SEQ ID NO:851, 857, 848 or 854.

As mentioned hereinabove and described in FIGS. 3a-3f , Table 12 andExample 10 of the Examples section which follows, the isolated promotersequences of the invention were capable of directing an expression of areporter gene (GUS) during fiber development.

According to an embodiment of the invention, the isolated polynucleotidesequence (the promoter sequence) of the invention is capable ofregulating expression of the heterologous polynucleotide sequence in anovule epidermal cell.

According to an embodiment of the invention, the ovule epidermal cellcomprises a plant fiber or a trichome.

The ability of polynucleotides of the invention and their products toregulate cotton fiber development can be determined directly on at leastone structural parameter of a cotton fiber such as fiber length or fiberfinesse, or fiber growth rate (further described hereinbelow).Alternatively, cotton fiber development can be determined indirectly byusing plant model systems for cotton fiber development such as trichomecells and root hairs [see Examples 7, 10 and 11 of the Examples sectionwhich follows and Wagner. G. J. et. al. (2004)].

By analyzing expression profiles of the isolated polynucleotides of theinvention and correlating between gene expression profile and fiberlength (see Example 3 and 4 of the Examples section), the presentinventors were able to determine the involvement of the biomoleculesequences (i.e., polynucleotides and polypeptides) of the invention infiber initiation and/or elongation and plant biomass.

Thus, according to yet another aspect of the invention there is provideda method of improving fiber quality and/or yield of a fiber producingplant. The method of this aspect of the invention is effected byexogenously expressing at least a functional portion of the isolatedpolypeptide of the invention in the fiber producing plant, therebyimproving the quality and/or yield of the fiber producing plant.

As used herein the phrase “fiber quality” refers to at least one fiberparameter which is agriculturally desired, or required in the fiberindustry (further described herein below). Examples of such parameters,include but are not limited to, fiber length, fiber strength, fiberfitness, fiber weight per unit length, maturity ratio and uniformity(further described hereinbelow).

Cotton fiber (lint) quality is typically measured according to fiberlength, strength and fineness. Accordingly, the lint quality isconsidered higher when the fiber is longer, stronger and finer.

As used herein the phrase “fiber yield” refers to the amount or quantityof fibers produced from the fiber producing plant.

As used herein the term “improving” refers to at least about 5%, atleast about 10%, at least about 15%, at least about 20%, at least about30%, at least about 40%, at least about 50%, at least about 60%, atleast about 70%, at least about 80%, change in fiber quality/yield ascompared to a native plant (i.e., not modified with the biomoleculesequences of the invention).

As used herein the phrase “exogenously expressing” refers to anexpression of at least a functional portion of the isolated polypeptideof the invention from an exogenous polynucleotide sequence (i.e., apolynucleotide sequence not derived from the host cell) introduced tothe host cell (a plant cell in this case).

The exogenous polynucleotide sequence of the invention is designed andconstructed to express at least a functional portion of the isolatedpolypeptide of the invention (e.g., the portion capable of improvingfiber yield/quality, increasing biomass). Accordingly, the exogenouspolynucleotide sequence may be a DNA or RNA sequence encoding apolypeptide molecule, capable of improving fiber yield or quantity.Alternatively, the exogenous polynucleotide may be a cis-actingregulatory region (e.g., SEQ ID NO:851, 848, or 857) which may beintroduced into the plant to increase expression of any polynucleotidewhich is involved in fiber development (e.g., sucrose phosphatesynthase, as described in U.S. Pat. No. 6,472,588; or any of theisolated polynucleotide sequences set forth by SEQ ID NOs:1, 12, 2, 17,10, 11, 8, 4, 7, 6, 5, 3, 9, 13, 14, 15, 16, 18-129, 259-534 or 535).

To express exogenous polynucleotides in plant cells, a polynucleotidesequence of the invention can be ligated into a nucleic acid constructsuitable for plant cell expression. Such a nucleic acid constructincludes at least one cis-acting regulatory element operably linked tothe isolated polynucleotide such as a promoter sequence for directingtranscription of the polynucleotide sequence in the cell in aconstitutive or inducible manner. The promoter may be homologous orheterologous to the transformed plant/cell.

Promoter sequences which can be used in accordance with this aspect ofthe invention are epidermal cell promoters.

For example, promoter sequences of each of the polynucleotide sequencesof the invention may be used in the nucleic acid constructs of theinvention.

According to an embodiment of this aspect of the invention the promoteris at least about 80%, at least about 81%, at least about 82%, at leastabout 83%, at least about 84%, at least about 85%, at least about 86%,at least about 87%, at least about 88%, at least about 89%, at leastabout 90%, at least about 91%, at least about 92%, at least about 93%,at least about 94%, at least about 95%, at least about 96%, at leastabout 97%, at least about 98%, at least about 99%, or 100% identical toSEQ ID NO:851, 848, 857, or 854, which is capable of regulatingexpression of at least one polynucleotide sequence operably linkedthereto in an ovule epidermal cell.

Other examples of cotton fiber-enhanced promoters include those of thecotton fiber-expressed genes E6 (John et al., Plant Mol. Biol.,30:297-306 (1996) and John et al., Proc. Natl. Acad. Sci.,93:12768-12773, 1996), H6 (John et al., Plant Physiol., 108:669-676,1995), FbL2A (Rinehart et al., Plant Physiol., 112:1331-1341, 1996) andJohn et al, Proc. Natl. Acad. Sci. USA, 93:12768-12773, 1996), rac(Delmer et al., Mol. Gen. Genet., 248:43-51, 1995); CelA (Pear et al.,Proc. Natl. Acad. Sci USA, 93:12637-12642, 1996); CAP (Kawai et al.,Plant Cell Physiol. 39:1380-1383, 1998); ACP (Song et al., Biochim.Biophys. Acta 1351:305-312, 1997); and LTP (Ma et al., Biochim. Biophys.Acta 1344:111-114, 1997). Other cotton fiber specific promoters aredisclosed in U.S. Pat. No. 5,495,070.

Other cotton fiber development promoters are disclosed in PCT NoIL2005/000627 to the present inventors (e.g., SEQ ID NO:85 or 91therein).

Other promoters which can be used in accordance with this aspect of theinvention are those that ensure expression only in specified organs,such as the leaf, root, tuber, seed, stem, flower or specified celltypes such as parenchyma, epidermal, trichome or vascular cells.

Promoters for enhancing expression in trichome cells are disclosed inWO2004/111183, to Evogene Ltd.

Promoters enhancing expression in vascular tissue include the CAD 2promoter (Samaj et al., Planta, 204:437-443, 1998), the Pt4C11 promoter(Hu et al., Proc. Natl. Acad. Sci. USA, 95:5407-5412, 1998), the C4Hpromoter (Meyer et al., Proc. Natl. Acad. Sci. USA, 95:6619-6623, 1998),the PtX3H6 and PtX14A9 promoters (Loopstra et al., Plant Mol. Biol.,27:277-291, 1995), the RolC promoter (Graham, Plant Mol. Biol.,33:729-735, 1997), the Hvhsp17 promoter (Raho et al., J. Expt. Bot.,47:1587-1594, 1996), and the COMT promoter (Capellades et al., PlantMol. Biol., 31:307-322, 1996).

Promoters enhancing expression in stem tissue include pith promoters(Datta, Theor. Appl. Genet., 97:20-30, 1998) and Ohta et al., Mol. Gen.Genet., 225:369-378, 1991), and the anionic peroxidase promoter (Klotzet al., Plant Mol. Biol., 36:509-520, 1998). Preferred promotersenhancing expression in phloem, cortex and cork, but not xylem or pith,include the Psam-1 promoter (Mijnsbrugge et al., Plant and CellPhysiol., 37:1108-1115, 1996).

Promoters enhancing expression in seeds include the phas promoter (Geestet al., Plant Mol. Biol. 32:579-588, 1996); the GluB-1 promoter (Takaiwaet al., Plant Mol. Biol. 30:1207-1221, 1996); the gamma-zein promoter(Torrent et al. Plant Mol. Biol. 34:139-149, 1997), and the oleosinpromoter (Sarmiento et al., The Plant Journal 11:783-796, 1997).

Other promoter sequences which mediate constitutive, inducible,tissue-specific or developmental stage-specific expression are disclosedin WO2004/081173 to Evogene Ltd.

Truncated or synthetic promoters including specific nucleotide regionsconferring tissue-enhanced expression may also be used, as exemplifiedby identification of regulatory elements within larger promotersconferring xylem-enhanced expression (Seguin et al., Plant Mol. Biol.,35:281-291, 1997; Torres-Schumann et al., The Plant Journal, 9:283-296,1996; and Leyva et al., The Plant Cell, 4:263-271, 1992).

The nucleic acid construct can be, for example, a plasmid, a bacmid, aphagemid, a cosmid, a phage, a virus or an artificial chromosome.Preferably, the nucleic acid construct of the invention is a plasmidvector, more preferably a binary vector.

The phrase “binary vector” refers to an expression vector which carriesa modified T-region from Ti plasmid, enable to be multiplied both in E.coli and in Agrobacterium cells, and usually comprising reporter gene(s)for plant transformation between the two boarder regions. A binaryvector suitable for the invention includes pBI2113, pBI121, pGA482,pGAH, pBIG, pBI101 (Clonetech), pPI (see Examples 5 and 10 of theExamples section which follows) or modifications thereof.

The nucleic acid construct of the invention can be utilized to transforma host cell (e.g., bacterial, plant) or plant.

As used herein, the terms “transgenic” or “transformed” are usedinterchangeably referring to a cell or a plant into which cloned geneticmaterial has been transferred.

In stable transformation, the nucleic acid molecule of the invention isintegrated into the plant genome, and as such it represents a stable andinherited trait.

In transient transformation, the nucleic acid molecule is expressed bythe cell transformed but not integrated into the genome, and as suchrepresents a transient trait.

There are various methods of introducing foreign genes into bothmonocotyledonous and dicotyledonous plants (Potrykus, I. (1991). AnnuRev Plant Physiol Plant Mol Biol 42, 205-225; Shimamoto, K. et al.(1989). Fertile transgenic rice plants regenerated from transformedprotoplasts. Nature (1989) 338, 274-276).

The principal methods of the stable integration of exogenous DNA intoplant genomic DNA includes two main approaches:

-   -   (i) Agrobacterium-mediated gene transfer. See: Klee, H. J. et        al. (1987). Annu Rev Plant Physiol 38, 467-486; Klee, H. J. and        Rogers, S. G. (1989). Cell Culture and Somatic Cell Genetics of        Plants, Vol. 6, Molecular Biology of Plant Nuclear Genes, pp.        2-25, J. Schell and L. K. Vasil, eds., Academic Publishers, San        Diego, Calif.; and Gatenby, A. A. (1989). Regulation and        Expression of Plant Genes in Microorganisms, pp. 93-112, Plant        Biotechnology, S. Kung and C. J. Arntzen, eds., Butterworth        Publishers, Boston, Mass.

(ii) Direct DNA uptake. See, e.g.: Paszkowski, J. et al. (1989). CellCulture and Somatic Cell Genetics of Plants, Vol. 6, Molecular Biologyof Plant Nuclear Genes, pp. 52-68, J. Schell and L. K. Vasil, eds.,Academic Publishers, San Diego, Calif.; and Toriyama, K. et al. (1988).Bio/Technol 6, 1072-1074 (methods for direct uptake of DNA intoprotoplasts). See also: Zhang et al. (1988). Plant Cell Rep 7, 379-384;and Fromm, M. E. et al. (1986). Stable transformation of maize aftergene transfer by electroporation. Nature 319, 791-793 (DNA uptakeinduced by brief electric shock of plant cells). See also: Klein et al.(1988). Bio/Technology 6, 559-563; McCabe, D. E. et al. (1988). Stabletransformation of soybean (Glycine max) by particle acceleration.Bio/Technology 6, 923-926; and Sanford, J. C. (1990). Biolistic planttransformation. Physiol Plant 79, 206-209 (DNA injection into plantcells or tissues by particle bombardment). See also: Neuhaus, J. M. etal. (1987). Theor Appl Genet 75, 30-36; and Neuhaus, J. M. andSpangenberg, G. C. (1990). Physiol Plant 79, 213-217 (use ofmicropipette systems). See U.S. Pat. No. 5,464,765 (glass fibers orsilicon carbide whisker transformation of cell cultures, embryos orcallus tissue). See also: DeWet, J. M. J. et al. (1985). “Exogenous genetransfer in maize (Zea mays) using DNA-treated pollen,” ExperimentalManipulation of Ovule Tissue, G. P. Chapman et al., eds., Longman, NewYork-London, pp. 197-209; and Ohta, Y. (1986). High-Efficiency GeneticTransformation of Maize by a Mixture of Pollen and Exogenous DNA. ProcNatl Acad Sci USA 83, 715-719 (direct incubation of DNA with germinatingpollen).

The Agrobacterium-mediated system includes the use of plasmid vectorsthat contain defined DNA segments which integrate into the plant genomicDNA. Methods of inoculation of the plant tissue vary depending upon theplant species and the Agrobacterium delivery system. A widely usedapproach is the leaf-disc procedure, which can be performed with anytissue explant that provides a good source for initiation of whole-plantdifferentiation (Horsch, R. B. et al. (1988). “Leaf disctransformation.” Plant Molecular Biology Manual A5, 1-9, Kluwer AcademicPublishers, Dordrecht). A supplementary approach employs theAgrobacterium delivery system in combination with vacuum infiltration.The Agrobacterium system is especially useful for in the creation oftransgenic dicotyledenous plants.

There are various methods of direct DNA transfer into plant cells. Inelectroporation, the protoplasts are briefly exposed to a strongelectric field, opening up mini-pores to allow DNA to enter. Inmicroinjection, the DNA is mechanically injected directly into the cellsusing micropipettes. In microparticle bombardment, the DNA is adsorbedon microprojectiles such as magnesium sulfate crystals or tungstenparticles, and the microprojectiles are physically accelerated intocells or plant tissues.

Following stable transformation, plant propagation occurs. The mostcommon method of plant propagation is by seed. The disadvantage ofregeneration by seed propagation, however, is the lack of uniformity inthe crop due to heterozygosity, since seeds are produced by plantsaccording to the genetic variances governed by Mendelian rules. In otherwords, each seed is genetically different and each will grow with itsown specific traits. Therefore, it is preferred that the regeneration beeffected such that the regenerated plant has identical traits andcharacteristics to those of the parent transgenic plant. The preferredmethod of regenerating a transformed plant is by micropropagation, whichprovides a rapid, consistent reproduction of the transformed plants.

Micropropagation is a process of growing second-generation plants from asingle tissue sample excised from a selected parent plant or cultivar.This process permits the mass reproduction of plants having thepreferred tissue and expressing a fusion protein. The newly generatedplants are genetically identical to, and have all of the characteristicsof, the original plant. Micropropagation allows for mass production ofquality plant material in a short period of time and offers a rapidmultiplication of selected cultivars with preservation of thecharacteristics of the original transgenic or transformed plant. Theadvantages of this method of plant cloning include the speed of plantmultiplication and the quality and uniformity of the plants produced.

Micropropagation is a multi-stage procedure that requires alteration ofculture medium or growth conditions between stages. The micropropagationprocess involves four basic stages: stage one, initial tissue culturing;stage two, tissue culture multiplication; stage three, differentiationand plant formation; and stage four, greenhouse culturing and hardening.During stage one, the tissue culture is established and certifiedcontaminant-free. During stage two, the initial tissue culture ismultiplied until a sufficient number of tissue samples are produced tomeet production goals. During stage three, the newly grown tissuesamples are divided and grown into individual plantlets. At stage four,the transformed plantlets are transferred to a greenhouse for hardeningwhere the plants' tolerance to light is gradually increased so that theycan continue to grow in the natural environment.

Although stable transformation is presently preferred, transienttransformation of, for instance, leaf cells, meristematic cells, or thewhole plant is also envisaged by the invention.

Transient transformation can be effected by any of the direct DNAtransfer methods described above or by viral infection using modifiedplant viruses.

Viruses that have been shown to be useful for the transformation ofplant hosts include cauliflower mosaic virus (CaMV), tobacco mosaicvirus (TMV), and baculovirus (BV). Transformation of plants using plantviruses is described in, for example: U.S. Pat. No. 4,855,237 (beangolden mosaic virus, BGMV); EPA 67,553 (TMV); Japanese PublishedApplication No. 63-14693 (TMV); EPA 194,809 (BV); EPA 278,667 (BV); andGluzman, Y. et al. (1988). Communications in Molecular Biology: ViralVectors, Cold Spring Harbor Laboratory, New York, pp. 172-189. The useof pseudovirus particles in expressing foreign DNA in many hosts,including plants, is described in WO 87/06261.

Construction of plant RNA viruses for the introduction and expression ofnon-viral exogenous nucleic acid sequences in plants is demonstrated bythe above references as well as by: Dawson, W. O. et al. (1989). Atobacco mosaic virus-hybrid expresses and loses an added gene. Virology172, 285-292; French, R. et al. (1986) Science 231, 1294-1297; andTakamatsu, N. et al. (1990). Production of enkephalin in tobaccoprotoplasts using tobacco mosaic virus RNA vector. FEBS Lett 269, 73-76.

If the transforming virus is a DNA virus, one skilled in the art maymake suitable modifications to the virus itself. Alternatively, thevirus can first be cloned into a bacterial plasmid for ease ofconstructing the desired viral vector with the foreign DNA. The viruscan then be excised from the plasmid. If the virus is a DNA virus, abacterial origin of replication can be attached to the viral DNA, whichis then replicated by the bacteria. Transcription and translation of theDNA will produce the coat protein, which will encapsidate the viral DNA.If the virus is an RNA virus, the virus is generally cloned as a cDNAand inserted into a plasmid. The plasmid is then used to make all of theplant genetic constructs. The RNA virus is then transcribed from theviral sequence of the plasmid, followed by translation of the viralgenes to produce the coat proteins which encapsidate the viral RNA.

Construction of plant RNA viruses for the introduction and expression inplants of non-viral exogenous nucleic acid sequences, such as thoseincluded in the construct of the invention, is demonstrated in the abovereferences as well as in U.S. Pat. No. 5,316,931.

In an embodiment, there is provided for insertion a plant viral nucleicacid, comprising a deletion of the native coat protein coding sequencefrom the viral nucleic acid, a non-native (foreign) plant viral coatprotein coding sequence, and a non-native promoter, preferably thesubgenomic promoter of the non-native coat protein coding sequence, andcapable of expression in the plant host, packaging of the recombinantplant viral nucleic acid, and ensuring a systemic infection of the hostby the recombinant plant viral nucleic acid. Alternatively, the nativecoat protein coding sequence may be made non-transcribable by insertionof the non-native nucleic acid sequence within it, such that anon-native protein is produced. The recombinant plant viral nucleic acidconstruct may contain one or more additional non-native subgenomicpromoters. Each non-native subgenomic promoter is capable oftranscribing or expressing adjacent genes or nucleic acid sequences inthe plant host and incapable of recombination with each other and withnative subgenomic promoters. In addition, the recombinant plant viralnucleic acid construct may contain one or more cis-acting regulatoryelements, such as enhancers, which bind a trans-acting regulator andregulate the transcription of a coding sequence located downstreamthereto. Non-native nucleic acid sequences may be inserted adjacent tothe native plant viral subgenomic promoter or the native and non-nativeplant viral subgenomic promoters if more than one nucleic acid sequenceis included. The non-native nucleic acid sequences are transcribed orexpressed in the host plant under control of the subgenomic promoter(s)to produce the desired products.

In an embodiment of the invention, a recombinant plant viral nucleicacid construct is provided as in the first embodiment except that thenative coat protein coding sequence is placed adjacent to one of thenon-native coat protein subgenomic promoters instead of adjacent to anon-native coat protein coding sequence.

In an embodiment of the invention, a recombinant plant viral nucleicacid construct is provided comprising a native coat protein gene placedadjacent to its subgenomic promoter and one or more non-nativesubgenomic promoters inserted into the viral nucleic acid construct. Theinserted non-native subgenomic promoters are capable of transcribing orexpressing adjacent genes in a plant host and are incapable ofrecombination with each other and with native subgenomic promoters.Non-native nucleic acid sequences may be inserted adjacent to thenon-native subgenomic plant viral promoters such that the sequences aretranscribed or expressed in the host plant under control of thesubgenomic promoters to produce the desired product.

In an embodiment of the invention, a recombinant plant viral nucleicacid construct is provided as in the third embodiment except that thenative coat protein coding sequence is replaced by a non-native coatprotein coding sequence.

Viral vectors are encapsidated by expressed coat proteins encoded byrecombinant plant viral nucleic acid constructs as describedhereinabove, to produce a recombinant plant virus. The recombinant plantviral nucleic acid construct or recombinant plant virus is used toinfect appropriate host plants. The recombinant plant viral nucleic acidconstruct is capable of replication in a host, systemic spread withinthe host, and transcription or expression of one or more foreign genes(isolated nucleic acid) in the host to produce the desired protein.

In addition to the above, the nucleic acid molecule of the invention canalso be introduced into a chloroplast genome thereby enablingchloroplast expression.

A technique for introducing exogenous nucleic acid sequences to thegenome of the chloroplasts is known. This technique involves thefollowing procedures. First, plant cells are chemically treated so as toreduce the number of chloroplasts per cell to about one. Then, theexogenous nucleic acid is introduced into the cells preferably viaparticle bombardment, with the aim of introducing at least one exogenousnucleic acid molecule into the chloroplasts. The exogenous nucleic acidis selected by one ordinarily skilled in the art to be capable ofintegration into the chloroplast's genome via homologous recombination,which is readily effected by enzymes inherent to the chloroplast. Tothis end, the exogenous nucleic acid comprises, in addition to a gene ofinterest, at least one nucleic acid sequence derived from thechloroplast's genome. In addition, the exogenous nucleic acid comprisesa selectable marker, which by sequential selection procedures serves toallow an artisan to ascertain that all or substantially all copies ofthe chloroplast genome following such selection include the exogenousnucleic acid. Further details relating to this technique are found inU.S. Pat. Nos. 4,945,050 and 5,693,507, which are incorporated herein byreference. A polypeptide can thus be produced by the protein expressionsystem of the chloroplast and become integrated into the chloroplast'sinner membrane.

It will be appreciated that the generation of fiber producing plant ofdesired traits according to the invention can also be effected bycrossing each of the above genetically modified plants with wild type,hybrid or transgenic plants, using methods which are well known in theart.

Once the transgenic plants of the invention are generated, fibers areharvested (for example by mechanical picking and/or hand-stripping) andfiber yield and quality is determined.

The following describes methods of qualifying cotton fibers.

Fiber length—Instruments such as a fibrograph and HVI (high volumeinstrumentation) systems are used to measure the length of the fiber.HVI instruments compute length in terms of “mean” and “upper half mean”(UHM) length. The mean is the average length of all the fibers while UHMis the average length of the longer half of the fiber distribution.

Fiber strength—As mentioned, fiber strength is usually defined as theforce required to break a bundle of fibers or a single fiber. In HVItesting the breaking force is converted to “grams force per tex unit.”This is the force required to break a bundle of fibers that is one texunit in size. In HVI testing the strength is given in grams per texunits (grams/tex). Fibers can be classified as low strength (e.g., 19-22gms/tex), average strength (e.g., 23-25 gms/tex), high strength (e.g.,26-28 gms/tex), and very high strength (e.g., 29-36 gms/tex).

Fiber fineness a and fiber weight per unit length—increased fiberfineness is likely attributable to increased fiber wall thicknessyielding more weight per unit length.

Maturity ratio—is a measure of the relative amount of cellulose in thefiber cross-section.

Uniformity—The degree to which the fibers in a sample are uniform isbased on the ratio of mean length to the upper half mean length, givenas a percentage.

Micronaire—The micronaire reading of a fiber is obtained from a porousair flow test. The test is conducted as follows. A weighed sample ofcotton is compressed to a given volume and controlled air flow is passedthrough the sample. The resistance to the air flow is read as micronaireunits. The micronaire readings reflect a combination of maturity andfineness. Since the fiber diameter of fibers within a given variety ofcotton is fairly consistent, the micronaire index will more likelyindicate maturity variation rather than variations in fineness. Amicronaire reading of 2.6-2.9 is low while 3.0-3.4 is below average,3.5-4.9 is average and 5.0 and up are high. For most textileapplications a micronaire of 3.5-4.9 is used. Anything higher than thisis usually not desirable. It will be appreciated though, that differentapplications require different fiber properties. Thus, it is understoodthat a fiber property that is disadvantageous in one application mightbe advantageous in another.

As is illustrated in the Examples section, which follows, biomoleculesequences of the invention are capable of increasing trichome/leaf hairnumber and length, as well as seed hair. As such biomolecules of theinvention can be used to generate transgenic plants with increasedtrichome number/length which better deter herbivores, guide the path ofpollinators, or affect photosynthesis, leaf temperature, or water lossthrough increased light reflectance. Additionally such transgenic plantsmay be used for the compartmentalized production of recombinant proteinsand chemicals in trichomes, as described in details in WO2004/111183 toEvogene Ltd.

The present inventors have also found that polynucleotide andpolypeptide sequences of the invention are capable of increasing abiomass of a plant. It will be appreciated that the ability of thepolypeptides of the invention to increase plant yield/biomass/vigor isinherent to their ability to promote the increase in plant cell-size orvolume (as described herein).

Thus, the invention also envisages a method of increasing abiomass/vigor/yield of a plant. This is effected by upregulatingexpression and/or activity of at least one of the polynucleotides of theinvention, as described above.

As used herein the phrase “plant biomass” refers to the amount orquantity of tissue produced from the plant in a growing season, whichcould also determine or affect the plant yield or the yield per growingarea.

As used herein the phrase “plant vigor” refers to the amount or quantityof tissue produced from the plant in a given time. Hence increase vigorcould determine or affect the plant yield or the yield per growing timeor growing area.

As used herein the phrase “plant yield” refers to the amount or quantityof tissue produced and harvested as the plant produced product. Henceincrease yield could affect the economic benefit one can obtain from theplant in a certain growing are and/or growing time.

As used herein the term “increasing” refers to at least about 5%, atleast about 10%, at least about 15%, at least about 20%, at least about30%, at least about 40%, at least about 50%, at least about 60%, atleast about 70%, at least about 80%, increase in plantyield/biomass/vigor/or tolerance to abiotic stress (further describedbelow) as compared to a native plant (i.e., not modified with thebiomolecule sequences of the invention).

As the sequences were elected by their ability to increase root tips andfibers the disclosed sequences may be used to increase tolerance orimprove resistance to abiotic stress.

The phrase “abiotic stress” used herein refers to any adverse effect onmetabolism, growth, reproduction and/or viability of a plant.Accordingly, abiotic stress can be induced by suboptimal environmentalgrowth conditions such as, for example, salinity, drought, flooding, lowor high temperature, heavy metal toxicity, anaerobiosis, nutrientdeficiency, atmospheric pollution or UV irradiation.

The phrase “abiotic stress tolerance” as used herein refers to theability of a plant exogenously expressing the biomolecule sequences ofthe invention to endure an abiotic stress without suffering asubstantial alteration in metabolism, growth, productivity and/orviability as compared to a native plant (i.e., not modified with thebiomolecule sequences of the invention) under the same abiotic stressconditions.

Additionally or alternatively, such parameters can be measured in plantsexogenously expressing the biomolecule sequences of the invention andcan be compared to the same parameters as measured in native plants(i.e., not modified with the biomolecule sequences of the invention,e.g., wild type plants) after exposing the plants to the same abioticstress conditions.

It will be appreciated that any plant is envisaged in accordance withthese embodiments of the invention. A suitable plant for use with themethod of the invention can be any monocotyledonous or dicotyledonousplant including, but not limited to, maize, wheat, barely, rye, oat,rice, soybean, peanut, pea, lentil and alfalfa, cotton, rapeseed,canola, pepper, sunflower, potato, tobacco, tomato, eggplant,eucalyptus, a tree, an ornamental plant, a perennial grass and a foragecrop, coniferous plants, moss, algae, as well as other plants listed inWorld Wide Web (dot) nationmaster (dot) com/encyclopedia/Plantae).

The invention also encompasses a method of producing cotton fibers by(a) generating a transgenic cotton plant exogenously expressing theisolated polypeptide of the invention and (b) harvesting the fibers ofthe transgenic cotton plant.

Thus, the invention is of high agricultural value for promoting theyield of commercially desired crops (e.g., biomass of vegetative organsuch as poplar wood, or reproductive organ such as number of seeds orseed biomass).

As is further shown in FIGS. 6 and 7 and described in Example 11 of theExamples section which follows, the present inventors have constructedvectors designed to express a cotton fiber developing gene (e.g., CT20;SEQ ID NO:881) under a constitutive promoter (e.g., 35S promoter; SEQ IDNO:841) and a reporter gene (e.g., GFP; SEQ ID NO:871) under thetranscriptional regulation of a cotton fiber developing promoter (e.g.,CT2 promoter; SEQ ID NO: 873), such that expression of the reporter genepinpoints on the fibers which were transformed with the construct (e.g.,by observing the fibers with the appropriate light, e.g., UV light todetect the GFP staining).

Thus, according to another aspect of the invention, there is provided anucleic acid construct comprising: (i) a first polynucleotide sequencewhich comprises a reporter gene operably linked to a fiber-specificpromoter; and (ii) a second polynucleotide sequence which comprises aheterologous nucleic acid sequence encoding a polypeptide-of-interestoperably linked to a promoter.

It will be appreciated that the first and second polynucleotidesequences can be also constructed each in a separate nucleic acidconstruct which together form a nucleic acid construct system.

Thus, according to yet another aspect of the invention, there isprovided a nucleic acid construct system comprising: (i) a first nucleicacid construct which comprises a first polynucleotide sequencecomprising a reporter gene operably linked to a fiber-specific promoter;and (ii) a second nucleic acid construct which comprises a secondpolynucleotide sequence comprising a heterologous nucleic acid sequenceencoding a polypeptide-of-interest operably linked to a promoter.

The fiber-specific promoter can be any promoter known to regulate fiberdevelopment (e.g., enhance fiber development) or which is specificallyexpressed in fibers. Non-limiting examples of fiber-specific promotersinclude the CT2 promoter as set forth by SEQ ID NO:873; the CT4 promoteras set forth by SEQ ID NO:848; the CT74 promoter set forth by SEQ IDNO:851, or the promoters set forth by SEQ ID NO:857 or 854.

The reporter gene can be any nucleic acid coding sequence encoding adetectable polypeptide (i.e., a polypeptide which can be detectedfollowing expression in a host cell). Non-limiting examples of reportergenes include the GFP coding sequence (e.g., SEQ ID NO:871), theGUSIntron (SEQ ID NO:872) and the cDNA encoding a non-fluorescentHaloTag protein (GenBank Accession No. AY773970) which followingexpression in a cell is interacted with an appropriate HaloTag ligandincluding a reactive linker that covalently binds to the HaloTag proteinand a flexible reporter group that can be a fluorophore (Lang C, et al.,2006, J. Exp. Bot. 57: 2985-92).

The polypeptide-of-interest which is expressed in the plant can be anypolypeptide which is beneficial to the plant. For example, such apolypeptide can be a polypeptide which regulates fiber development suchas any of the isolated polypeptides described hereinabove (SEQ IDNOs:130, 141, 131, 146, 139, 140, 137, 133, 136, 135, 134, 132, 138,142, 143, 144, 145, 147-258 and 536-791) or in PCT IL2005/000627 toEvogene Ltd. (e.g., the polypeptide encoded by CT20 coding sequence setforth by SEQ ID NO:881).

Non-limiting examples of heterologous nucleic acid sequences encodingthe polypeptide-of-interest include any of the isolated polynucleotidesequences of the invention (e.g., SEQ ID NOs:1-129, and 259-535).

According to an embodiment of the invention the heterologous nucleicacid sequence is operably linked to a constitutive promoter (e.g., the35S promoter as set forth by SEQ ID NO:841; Actin promoter (McElroy etal, Plant Cell, 2: 163-171, 1990); CaMV 19S (Nilsson et al., Physiol.Plant 100:456-462, 1997); GOS2 (de Pater et al, Plant J November;2(6):837-44, 1992); Rice cyclophilin (Bucholz et al, Plant Mol Biol.25(5):837-43, 1994); ubiquitin (Christensen et al, Plant Mol. Biol. 18:675-689, 1992); Maize H3 histone (Lepetit et al, Mol. Gen. Genet. 231:276-285, 1992); Actin 2(An et al, Plant J. 10(1); 107-121, 1996).

According to an embodiment of the invention, the heterologous nucleicacid sequence is operably linked to a fiber-specific promoter (e.g., theCT2 promoter as set forth by SEQ ID NO:873 or the CT4 promoter as setforth by SEQ ID NO:848).

Non-limiting examples of suitable nucleic acid constructs are depictedin FIGS. 6 and 7.

Such nucleic acid constructs/systems can be used to transiently expressa polypeptide-of-interest (e.g., the cotton fiber developingpolypeptide) in a plant (e.g., a cotton plant).

While further reducing the invention to practice, the present inventorshave devised a novel approach for transiently expressing apolypeptide-of-interest (e.g., a cotton fiber developing polypeptide) incotton ovule cells by injecting a nucleic acid construct encoding thepolypeptide-of-interest into a developed cotton ball.

As is shown in FIGS. 4a-4c and describe in Example 11 of the Examplessection which follows, cotton balls which were injected with the nucleicacid sequences at e.g., 1 and 8 DPA expressed the reporter gene(beta-glucuronidase, GUS) in the developed ball. In addition, transientexpression of the binary vectors comprising fiber developing gene (e.g.,expansin or CT20) resulted in a significant effect on fiber length(FIGS. 5a-5c , Table 13, Example 11 of the Examples section).

Thus, according to another aspect of the invention, there is provided amethod of expressing a polypeptide-of-interest in a cotton plant. Themethod is effected by injecting to a cotton ball of the cotton plant anucleic acid construct which comprises a nucleic acid sequence encodingthe polypeptide-of-interest, there by expressing thepolypeptide-of-interest in the cotton plant.

As used herein the phrase “cotton ball” refers to the cotton fruit atvarious developmental stages [e.g., 0, 2, 4 and 6 days post anthesis(DPA)].

Injection of the nucleic acid construct can be injected directly to thecotton ball, using e.g., a 1-ml syringe with a 0.5-316-mm needle (BDPastipak) (See Example 11 of the Examples section). Briefly, the needleis introduced to 1 to 2 mm in depth into the fruit tissue, and theinfiltration solution containing the nucleic acid construct is injectedinto the fruit.

According to an embodiment of the invention expressing is effected at anovule cell of the cotton plant.

As shown in Example 11 of the examples section, the nucleic acidconstructs (e.g., those described in FIG. 6 or 7) were transfected intoa cell (e.g., agrobacterium cell), and the transformed cells are furtherinjected to the cotton ball.

Methods of transfecting nucleic acid constructs into agrobacteria areknown in the art and further described hereinabove and in Example 11 ofthe Examples section which follows.

Thus, according to an embodiment of the invention, the nucleic acidconstruct/system of the invention is comprised in agrobacteria.

As used herein the term “about” refers to ±10%.

The terms “comprises”, “comprising”, “includes”, “including”, “having”and their conjugates mean “including but not limited to”.

The term “consisting of” means “including and limited to”.

The term “consisting essentially of” means that the composition, methodor structure may include additional ingredients, steps and/or parts, butonly if the additional ingredients, steps and/or parts do not materiallyalter the basic and novel characteristics of the claimed composition,method or structure.

As used herein, the singular form “a”, “an” and “the” include pluralreferences unless the context clearly dictates otherwise. For example,the term “a compound” or “at least one compound” may include a pluralityof compounds, including mixtures thereof.

As used herein the term “method” refers to manners, means, techniquesand procedures for accomplishing a given task including, but not limitedto, those manners, means, techniques and procedures either known to, orreadily developed from known manners, means, techniques and proceduresby practitioners of the chemical, pharmacological, biological,biochemical and medical arts.

It is appreciated that certain features of the invention, which are, forclarity, described in the context of separate embodiments, may also beprovided in combination in a single embodiment. Conversely, variousfeatures of the invention, which are, for brevity, described in thecontext of a single embodiment, may also be provided separately or inany suitable subcombination or as suitable in any other describedembodiment of the invention. Certain features described in the contextof various embodiments are not to be considered essential features ofthose embodiments, unless the embodiment is inoperative without thoseelements.

Various embodiments and aspects of the invention as delineatedhereinabove and as claimed in the claims section below find experimentalsupport in the following examples.

EXAMPLES

Reference is now made to the following examples, which together with theabove descriptions illustrate some embodiments of the invention in a nonlimiting fashion.

Reference is now made to the following examples, which together with theabove descriptions illustrate the invention in a non limiting fashion.

Generally, the nomenclature used herein and the laboratory proceduresutilized in the invention include molecular, biochemical,microbiological and recombinant DNA techniques. Such techniques arethoroughly explained in the literature. See, for example, “MolecularCloning: A laboratory Manual” Sambrook et al., (1989); “CurrentProtocols in Molecular Biology” Volumes I-III Ausubel, R. M., ed.(1994); Ausubel et al., “Current Protocols in Molecular Biology”, JohnWiley and Sons, Baltimore, Md. (1989); Perbal, “A Practical Guide toMolecular Cloning”, John Wiley & Sons, New York (1988); Watson et al.,“Recombinant DNA”, Scientific American Books, New York; Birren et al.(eds) “Genome Analysis: A Laboratory Manual Series”, Vols. 1-4, ColdSpring Harbor Laboratory Press, New York (1998); methodologies as setforth in U.S. Pat. Nos. 4,666,828; 4,683,202; 4,801,531; 5,192,659 and5,272,057; “Cell Biology: A Laboratory Handbook”, Volumes I-III Cellis,J. E., ed. (1994); “Current Protocols in Immunology” Volumes I-IIIColigan J. E., ed. (1994); Stites et al. (eds), “Basic and ClinicalImmunology” (8th Edition), Appleton & Lange, Norwalk, Conn. (1994);Mishell and Shiigi (eds), “Selected Methods in Cellular Immunology”, W.H. Freeman and Co., New York (1980); available immunoassays areextensively described in the patent and scientific literature, see, forexample, U.S. Pat. Nos. 3,791,932; 3,839,153; 3,850,752; 3,850,578;3,853,987; 3,867,517; 3,879,262; 3,901,654; 3,935,074; 3,984,533;3,996,345; 4,034,074; 4,098,876; 4,879,219; 5,011,771 and 5,281,521;“Oligonucleotide Synthesis” Gait, M. J., ed. (1984); “Nucleic AcidHybridization” Hames, B. D., and Higgins S. J., eds. (1985);“Transcription and Translation” Hames, B. D., and Higgins S. J., Eds.(1984); “Animal Cell Culture” Freshney, R. I., ed. (1986); “ImmobilizedCells and Enzymes” IRL Press, (1986); “A Practical Guide to MolecularCloning” Perbal, B., (1984) and “Methods in Enzymology” Vol. 1-317,Academic Press; “PCR Protocols: A Guide To Methods And Applications”,Academic Press, San Diego, Calif. (1990); Marshak et al., “Strategiesfor Protein Purification and Characterization—A Laboratory CourseManual” CSHL Press (1996); all of which are incorporated by reference asif fully set forth herein. Other general references are providedthroughout this document. The procedures therein are believed to be wellknown in the art and are provided for the convenience of the reader. Allthe information contained therein is incorporated herein by reference.

Example 1 Identification of Gene Clusters Involved in Plant FiberDevelopment

Bioinformatics Analysis

In silico identification of cotton genes involved in fiberformation—Putative cotton genes involved in fiber formation wereselected from NCBI databases of cotton expressed sequence tags (ESTs)and cDNAs. The database sequences were clustered and assembled using theLEADS™ software (Compugen, Tel Aviv, Israel). Clustering resulted inmore than 18,700 clusters, each representing a different gene. Anexpression profile summary was compiled for each cluster by pooling allkeywords included in the sequence records comprising the cluster. Genesover-expressed in fiber initiation and elongation phase were isolated.The clusters were then screened to include polynucleotides originatingfrom libraries of addition elongated tissues such as root tips, xylemand tissues exposed to etiolating conditions. Since the main force thatacts in order to elongate the cell is the cell turgor, in addition toelongated tissues, the selected genes were compared to genes expressedunder abiotic stresses, mainly under drought stress (details of genesclustered and analyzed are summarized in Table 1, hereinbelow).Combining the different queries, a list of 56 predicted fiber improvinggene candidates was created. Those genes were further validated usingRNA expression analysis (qRT-PCR).

TABLE 1 Gene Clustering Results Output non-singelton contigs TIGR LEADSOrganism Sequences Contigs Sequences Contigs Cotton 92,338 14,325198,492 18,543 Tomato 148,522 16,247 209,693 16,322 Poplar 231,07224,382 — — Arabidopsis 327,875 19,863 — — Additional species (10)*1,855,997 174,045 3,076,554 167,956 Total 2655804 248,862 427,661 38,850Table 1: Gene clustering results. *The addition species that were usedare: maize, rice, sorghum, soybean, grape, canola, barley, strawberry,peach and melon.

Example 2 Analysis of mRNA Expression Profiles of Genes Involved inPlant Fiber Development

To study the RNA expression profile of candidate genes identified asdescribed in Example 1 above, a reverse transcription reaction followedby real time PCR (RT-qPCR) was performed on RNA extracted from cottonplants at different stages of fiber development, as follows.

Experimental Procedures

Quantitative Real Time PCR Analysis (qRT PCR)

To verify the levels of expression specificity and trait-association,Reverse Transcription following quantitative (Real-Time) PCR (RTqPCR)was performed. Total RNA was extracted from cotton plants at differentstages of fiber development (from the day of anthesis till day 20—postanthesis). To study the specificity of expression, RNA from othertissues of the cotton plants were collected and analyzed for controlexpression (i.e., young leaves, young stems, mature stems, young roots,sepals, petals, and stamen). For this purpose, RNA was extracted fromCotton tissue using Hot Borate RNA Extraction protocol according toWorld Wide Web(dot)eeob(dot)iastate(dot)edu/faculty/WendelJ/ultramicrorna(dot)html.Reverse transcription was effected using 1.5 μg total RNA, using 300 USuper Script II Reverse Transcriptase enzyme (Invitrogen), 225 ng randomdeoxynucleotide hexamers (Invitrogen), 500 μM dNTPs mix (Takara, Japan),0.2 volume of ×5 reverse transcriptase (RT) buffer (Invitrogen), 0.01 MDTT, 60 U RNAsin (Promega), DEPC treated double distilled water wasadded up to 37.5 μl. RT reactions were incubated for 50 minutes at 42°C., followed by 70° C. for 15 minutes. cDNA was diluted 1:20 in TrisEDTA, pH=8. 5 μl of the diluted cDNA was used for qRT-PCR.

Quantitative RT-PCR was performed on cDNA (5 μl), using ×1 SYBR GREENPCR master mix (Applied Biosystems), forward and reverse primers 0.3 μMeach. The ABI7000 real-time PCR machine was used with the followingconditions: 50° C. for 2 minutes, 95° C. for 10 minutes, 40 times of 95°C. for 15 sec and 1 minute at 60° C., followed by 95° C. for 15 seconds,60° C. for 60 seconds, and 70 times of 60° C. for 10 seconds+0.5° C.increase in each cycle. For each gene, a standard curve was preparedfrom a pool of RTs from all samples, in 5 dilutions (dilutions—1:60,1:200, 1:600, 1:2000, 1:10000). The standard curve plot [ct (cyclethreshold) vs. log (concentration)] should have R≥0.98 with anefficiency in the range of 100%±5%. The levels of expression (Qty)measured in the qPCR were calculated using the efficiency (E) of theamplification reaction and the corresponding C.T. (the cycle at whichthe samples crossed the threshold) Qty=E−C.T. The dissociation curvesobtained were inspected for the absence of unwanted additional PCRproducts or primer-dimers. Reactions were repeated at least twice. Thecalculation method is based in the fact that the efficiencies of thereactions of the GOI (gene-of-interest) and of the housekeeping genesare similar.

To normalize the expression level between the different tissues,specific primers were designed for specifically hybridizing with thefollowing housekeeping genes: Actin (GenBank Accession No. D88414 SEQ IDNO: 792, Forward and reverse primers are set forth in SEQ ID NOs:793 and794, respectively), GAPDH (SEQ ID NO:795), Forward and reverse primersare set forth in SEQ ID NOs:796 and 797, respectively), and RPL19(GenBank Accession No. AI729179, SEQ ID NO:798, Forward and reverseprimers are set forth in SEQ ID NOs:799 and 800, respectively).

Experimental Results

Using the above methodology it was possible to identify genes that showelevated expression during fiber elongation, as well as genes that showunique cotton fiber specificity. Genes that showed elevated expressionduring anthesis that decreases during fiber elongation were consideredgood candidates to be involved in fiber differentiation and initiation.Notably, the above-described quantification methodology did not provideabsolute expression levels, but provided good parameters for scoring therelative gene expression along fiber development as differences as highas over 1000 fold in the maximal levels of expression reached bydifferent genes were detected (Table 2, below).

56 cotton genes were evaluated for their expression profile in differenttissues of cotton (Gossypium hirsutum, var Acala).

Two main criteria were used to select cotton genes as candidates thatmay be involved in fiber development according to their RNA profiling,namely genes showing high degree of fiber expression specificity andgenes displaying an expression level, which changes concomitantly withfiber development. Seventeen genes met these selection criteria and werepredicted to improve fiber yield and quality. Expression profiles andannotation of the 17 selected genes are presented in Tables 2a and 2band Table 3, hereinbelow.

TABLE 2a Expression profiles of the 17 selected genes Gene ID/SEQ ID NO(nucleotide). 0 dpa 2 dpa 5 dpa 10 dpa 15 dpa 20 dpa 25 dpa CTF101/30.036 0.133 0.077 0.071 0.055 0.039 0.050 CTF110/4 0.407 3.192 1.0881.630 0.043 0.006 0.010 CTF111/5 0.050 0.899 0.649 0.901 0.217 0.0130.049 CTF113/6 0.015 0.012 0.013 0.009 0.005 0.001 0.001 CTF121/18 0.0560.020 0.039 0.021 0.013 0.001 CTF124/7 0.012 0.312 0.288 0.147 0.0260.002 CTF126/19 0.008 0.019 0.012 0.003 0.009 0.005 0.002 CTF130/200.000 0.006 0.003 0.002 0.001 0.000 0.000 CTF131/21 0.009 0.088 0.0500.019 0.011 0.004 0.012 CTF132/22 1.300 5.250 2.882 1.553 1.164 1.6440.567 CTF133/23 0.131 0.313 0.214 0.089 0.150 0.136 0.111 CTF134/241.221 0.245 0.232 0.116 0.153 0.369 0.227 CTF135/8 5.869 18.755 10.2434.512 2.033 1.162 1.934 CTF144/25 1.851 0.851 1.676 1.375 0.220 0.1860.010 CTF146/26 0.025 0.104 0.108 0.138 0.050 0.022 0.023 CTF150/270.009 0.190 0.092 0.102 0.046 0.001 0.001 CTF155/28 0.117 0.236 0.1520.188 0.145 0.176 0.337 Table 2a: Reverse-transcription followingquantitative PCR was performed using real-time PCR, on tissues of eitheryoung or mature cotton (G. hirsutum var Acala) plants. Relative amountsof mRNA of each gene are presented in all examined tissues. dpa—dayspost anthesis, of ovule and fibers tissues (until 10 dpa) or only fibertissue (after 10 dpa).

TABLE 2b Expression profiles of the 17 selected genes Gene ID/SEQ IDYoung Young Young NO (nucleotide). Sepals Petals roots leaves budsStamen Pestel 0 dpa CTF101/3 0.018 0.004 0.044 0.015 0.014 0.004 0.0130.036 CTF110/4 0.026 0.028 0.024 0.736 0.761 0.020 0.010 0.407 CTF111/50.015 0.996 0.002 0.031 0.024 0.152 3.288 0.050 CTF113/6 0.008 0.0020.283 0.002 0.003 0.084 0.002 0.015 CTF121/18 0.023 0.527 0.029 0.0010.005 0.680 1.079 0.056 CTF124/7 0.001 0.001 0.034 0.004 0.002 0.0000.003 0.012 CTF126/19 0.016 0.016 0.005 0.004 0.002 0.008 0.017 0.008CTF130/20 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 CTF131/210.008 0.077 0.001 0.001 0.006 0.083 0.043 0.009 CTF132/22 0.283 0.1520.035 0.496 1.126 0.059 0.286 1.300 CTF133/23 0.176 0.543 0.072 0.0420.035 1.117 0.370 0.131 CTF134/24 0.124 0.349 0.179 0.053 0.164 0.2891.343 1.221 CTF135/8 3.968 2.389 0.076 1.333 3.098 3.326 17.426 5.869CTF144/25 0.883 0.556 1.314 0.229 0.685 0.759 2.638 1.851 CTF146/260.023 0.252 0.029 0.007 0.016 0.067 0.091 0.025 CTF150/27 0.005 0.0100.000 0.000 0.002 0.079 0.002 0.009 CTF155/28 0.272 0.839 0.126 0.1080.151 7.598 1.447 0.117 Table 2b: Reverse-transcription followingquantitative PCR was performed using real-time PCR, on tissues of eitheryoung or mature cotton (G. hirsutum var Acala) plants. Relative amountsof mRNA of each gene are presented in all examined tissues. dpa—dayspost anthesis, of ovule and fibers tissues (until 10 dpa) or only fibertissue (after 10 dpa).

TABLE 3 Annotation of the 17 selected genes CTF# Annotation Pattern ofexpression Fiber specificity CTF101 GTPase Elongation No CTF110GDSL-motif lipase/hydrolase-like Elongation No protein CTF1113-ketoacyl-CoA synthase||fatty Elongation No acid elongase CTF113Raffinose synthase Elongation No CTF121 Pectin methylesterase PME1Elongation No CTF124 Similar to acid phosphatase Elongation Fiberspecific CTF126 Actin-depolymerizing factor 4 Elongation No CTF130RING-H2 finger protein ATL2M Elongation/Initiation Fiber specific CTF131Putative glucosyltransferase Elongation No CTF132 serine protease-likeprotein Elongation No CTF133 Proteasome subunit Elongation No CTF134Pectin methylesterase Elongation/Initiation No CTF135 Proteasome subunitalpha type 5 Elongation No CTF144 Ascorbate oxidase precursorElongation/Initiation No CTF146 protein kinase TMK1 Elongation No CTF150Putativepod-specific Elongation Fiber specific dehydrogenase SAC25CTF155 Snakin-1 Elongation Fiber specific Table 3: Annotation of the 17selected genes based on the NCBI data-base.

Example 3 Identifying Correlation Between Expression of Candidate Genesand Fiber Length

The correlation between fiber length and expression of the candidategenes was determined in 10 different cotton lines representing a widevariety of fiber length characteristics, as follows.

Experimental Procedures

Cotton Lines

The 10 different cotton lines representing wide variety of fiber lengthcharacteristics included earlier G. hirsutum varieties (SA217SD andSA68SD), G. hirsutum varieties (Tamcot, Macnair, DP90 and ZG236) F1hybrid of G. hirsutum and G. barbadense (Acalphi) and high quality ofpima type (G. barbadense) (S7 and Pima).

RNA Extraction

Fiber development stages, representing different fiber characteristic,at 5, 10 and 15 DPA were sampled and RNA was extracted as described inExample 2, hereinabove.

Fiber Length Assessment

Fiber length of the above lines was measured using a fibrograph. Thefibrograph system was used to compute length in terms of “Upper HalfMean” length. The upper half mean (UHM) is the average length of longerhalf of the fiber distribution. The fibrograph measures length in spanlengths at a given percentage point [World Wide Web (dot) cottoninc(dot)com/ClassificationofCotton/?Pg=4#Length].

Experimental Results

Ten different cotton lines were grown in Rehovot, Israel, and theirfiber length was measured. The fibers UHM values were measured and thecorrelation between RNA expression level and the fiber length wascalculated according to Pearson correlation [Hypertext Transfer Protocol(http)://davidmlane (dot) com/hyperstat/A34739 (dot) html], wherein “R”is the correlation coefficient, and the P value determines thesignificance of the correlation. Genes with R>0.4 and P<0.05 in at listone of the measured time points (i.e., 5, 10 or 15 dpa) have beenconsidered as related to fiber elongation and were further selected forcloning and validation (data are summarized in Table 4, hereinbelow).

TABLE 4 Correlation between RNA expression level and the fiber length 5dpa 10 dpa 15 dpa R P R P R P CTF101 0.51 0.03 0.56 0.02 CTF110 0.410.06 0.41 0.05 CTF111 0.35 0.10 0.40 0.07 CTF113 0.34 0.10 0.44 0.050.51 0.03 CTF121 0.72 0.00 0.65 0.01 CTF124 0.50 0.03 CTF126 0.47 0.04CTF131 0.49 0.03 CTF132 0.60 0.01 0.45 0.05 CTF133 0.69 0.01 CTF134 0.360.09 CTF135 0.30 0.13 CTF144 0.34 0.10 Table 4: The correlation betweenRNA expression level and the fiber length are presented for the threetime points (5 dpa, 10 dpa and 15 dpa) using the Pearson correlationcoefficient R and the p values.

Example 4 Production of Cotton Transcriptom and High ThroughputCorrelation Analysis Using Cotton Oligonucleotide Microarray

In order to conduct high throughput gene expression correlationanalysis, the present inventors used cotton oligonucleotide microarray,designed and produced by “Comparative Evolutionary Genomics of Cotton”[Hypertext Transfer Protocol (http)://cottonevolution (dot) info/). ThisCotton Oligonucleotide Microarray is composed of 12,006 Integrated DNATechnologies (IDT) oligonucleotides derived from an assembly of morethan 180,000 Gossypium ESTs sequenced from 30 cDNA libraries.

In order to define correlations between the levels of RNA expression andfiber length, fibers from 8 different cotton lines were analyzed. Thesefibers were selected showing very good fiber quality and high lint index(Pima types, originating from other cotton species, namely G.barbadense), different levels of quality and lint indexes from variousG. hirsutum lines: good quality and high lint index (Acala type), andpoor quality and short lint index (Tamcot type, and old varieties). Asummary of the fiber length of the different lines is provided in Table5.

Experimental Procedures

RNA Extraction

Fiber development stages, representing different fiber characteristics,at 5, 10 and 15 DPA were sampled and RNA was extracted as described inExample 2, hereinabove.

Fiber Length Assessment

Fiber length of the selected cotton lines was measured using fibrograph.The fibrograph system was used to compute length in terms of “Upper HalfMean” length. The upper half mean (UHM) is the average length of longerhalf of the fiber distribution. The fibrograph measures length in spanlengths at a given percentage point World Wide Web (dot) cottoninc (dot)com/ClassificationofCotton/?Pg=4#Length].

Experimental Results

Eight different cotton lines were grown in Rehovot, Israel, and theirfiber length was measured. The fibers UHM values are summarized in Table5 hereinbelow. The R square was calculated for each of the genes. Geneswith R square values greater than 0.8 and P<0.05 in at list one timepoint, or the average expression at the different time points, wereselected for further validation. The selected genes and their R squarevalues are summarizing in Table 6.

TABLE 5 Summary of the fiber length of the 8 different cotton linesLength (UHM) Cotton variety Mean STD SA 217 SD 0.89 0.04 SA 68 SD 1.010.03 Tamcot 1.06 0.01 DP 90 1.1 0.08 ZG 236 1.15 0.00 Coker 310 1.210.02 S7 1.26 0.02 Pima 1.36 0.00 Table 5: Presented are the means andstandard deviations (STD) of 8 different cotton lines.

TABLE 6 Correlation between RNA expression level and the fiber lengthSerial CTF No./ 5 dpa 10 dpa 15 dpa AVG No. SEQ ID NO: R P E R P E R P ER P E 1 CTF157/29 0.90 0.01 10.30 0.76 0.03 68.40 2 CTF158/30 0.79 0.0234.20 0.79 0.03 66.90 0.96 0.00 0.70 3 CTF159/31 0.79 0.02 33.20 0.970.00 0.60 4 CTF161/32 0.90 0.00 3.80 5 CTF162/9 0.71 0.05 82.10 0.910.00 8.70 6 CTF163/33 0.82 0.01 21.70 0.93 0.00 4.20 0.89 0.01 7.30 7CTF164/34 0.84 0.01 14.50 0.80 0.02 40.90 0.94 0.00 1.40 8 CTF165/1 0.920.00 2.20 0.93 0.00 5.20 0.91 0.01 4.80 9 CTF166/10 0.86 0.01 24.00 0.870.01 11.40 10 CTF167/2 0.90 0.01 12.90 0.90 0.01 5.20 11 CTF168/35 0.770.02 40.40 0.94 0.00 3.30 0.94 0.00 1.60 12 CTF169/11 0.97 0.00 0.80 13CTF170/36 0.84 0.01 14.60 0.91 0.00 9.50 0.95 0.00 1.10 14 CTF171/370.75 0.03 53.10 0.96 0.00 1.50 15 CTF172/12 0.77 0.02 41.10 0.81 0.0351.70 0.75 0.03 78.90 0.80 0.03 30.40 16 CTF173/13 0.93 0.00 1.10 0.700.05 129.80 0.78 0.04 38.60 17 CTF174/38 0.97 0.00 0.50 0.73 0.04 93.500.92 0.00 3.40 18 CTF175/14 0.90 0.00 3.90 0.83 0.02 20.00 19 CTF176/150.92 0.00 2.10 20 CTF177/16 0.88 0.01 18.40 0.89 0.00 6.60 0.90 0.015.20 21 CTF178/17 0.92 0.00 7.40 0.91 0.00 3.60 0.82 0.02 22.80 22CTF180/39 0.90 0.00 3.60 23 CTF181/40 24 CTF182/41 0.83 0.01 19.20 25CTF183/42 0.76 0.03 45.70 0.84 0.02 35.60 0.85 0.02 15.80 26 CTF184/430.82 0.02 47.70 0.78 0.04 39.30 27 CTF185/44 0.88 0.01 17.70 28CTF186/45 0.73 0.04 65.10 0.82 0.02 21.70 29 CTF187/46 0.87 0.00 7.700.75 0.03 76.50 0.75 0.05 51.00 30 CTF188/47 0.80 0.03 61.90 0.82 0.0324.60 31 CTF189/48 0.84 0.01 16.00 0.80 0.03 64.20 0.73 0.04 97.90 0.790.03 32.50 32 CTF190/49 0.74 0.04 60.70 0.89 0.01 13.90 33 CTF191/500.83 0.01 19.30 0.87 0.01 12.50 0.82 0.02 23.20 34 CTF192/51 0.87 0.0110.10 35 CTF193/52 0.79 0.04 70.20 0.85 0.01 19.30 0.86 0.01 12.70 36CTF194/53 0.85 0.01 12.50 0.81 0.02 36.70 0.88 0.01 9.50 37 CTF195/540.87 0.01 19.90 0.86 0.01 11.70 38 CTF196/55 39 CTF197/56 0.81 0.0352.20 0.72 0.05 112.50 40 CTF199/57 0.81 0.02 25.80 41 CTF200/58 0.760.03 66.10 42 CTF201/59 0.75 0.03 54.90 0.82 0.02 46.30 0.73 0.04 93.700.78 0.04 38.30 43 CTF202/60 0.84 0.02 36.60 44 CTF203/61 0.78 0.0236.70 0.78 0.04 73.80 0.82 0.02 23.60 45 CTF204/62 0.86 0.01 16.30 46CTF205/63 0.87 0.01 21.10 47 CTF206/64 0.87 0.01 21.70 0.87 0.01 11.1048 CTF207/65 0.79 0.03 68.40 0.77 0.02 58.90 0.83 0.02 18.90 49CTF208/66 0.83 0.01 16.80 50 CTF209/67 0.78 0.02 38.50 0.85 0.02 30.600.80 0.03 30.80 51 CTF210/68 0.87 0.00 10.90 52 CTF211/69 0.72 0.0576.80 0.83 0.02 43.90 0.88 0.01 8.40 53 CTF212/70 0.72 0.04 71.60 0.740.04 87.50 0.82 0.02 23.80 54 CTF213/71 0.83 0.01 18.30 0.71 0.05 122.7055 CTF214/72 56 CTF215/73 0.90 0.01 11.90 0.80 0.03 29.40 57 CTF216/740.87 0.01 23.10 58 CTF217/75 0.86 0.01 9.90 59 CTF218/76 0.88 0.01 17.3060 CTF219/77 0.83 0.02 19.50 61 CTF220/78 0.90 0.00 6.50 62 CTF221/790.83 0.02 43.20 63 CTF222/80 0.78 0.04 80.50 0.82 0.01 29.80 64CTF223/81 0.84 0.01 14.30 0.85 0.02 29.60 0.89 0.01 7.40 65 CTF224/820.70 0.05 89.90 0.83 0.02 43.50 66 CTF225/83 0.87 0.01 8.70 0.84 0.0236.50 0.77 0.04 41.20 67 CTF226/84 0.73 0.04 70.00 0.77 0.03 62.20 0.810.03 27.90 68 CTF227/85 0.80 0.03 31.40 69 CTF229/86 0.87 0.01 23.40 70CTF230/87 0.83 0.01 18.20 0.87 0.01 12.50 0.84 0.02 18.30 71 CTF231/880.81 0.03 25.10 72 CTF232/89 0.82 0.02 48.10 0.71 0.05 114.50 73CTF233/90 0.82 0.01 22.40 74 CTF234/91 0.78 0.02 51.70 0.87 0.01 9.70 75CTF235/92 0.88 0.01 18.70 0.72 0.07 64.00 76 CTF236/93 0.89 0.01 15.600.81 0.03 27.10 77 CTF237/94 0.88 0.00 6.70 0.78 0.04 73.20 0.85 0.0215.40 78 CTF238/95 0.81 0.03 27.80 79 CTF239/96 0.87 0.01 10.60 Table 6:The correlation between RNA expression level of 79 genes and the fiberlength is presented for the average and the three time points (5 dpa, 10dpa and 15 dpa) using the Pearson correlation coefficient (R) and the pvalues. The efficiency (E) of the amplification reaction is alsopresented.

The 79 genes provided in Table 6, hereinabove, met the selectioncriteria of R square values greater than 0.8 and P<0.05. (R and P werecalculated according to Pearson correlation) [Hypertext TransferProtocol] (http)://davidmlane (dot) com/hyperstat/A34739 (dot) html).

Overall, 96 cotton genes (the 17 genes were described in Examples 2 and3, and the 79 genes described in Example 4) were identified here asinvolved in cotton fiber development. In addition, 33 genes (SEQ IDNOs:97-129) were identified from other plant species, sharing commonfeatures and sequence homology to one or more of the cotton genes.Altogether, 129 genes were identified using bioinformatics tools andexpression studies in the present study as being able to positivelyaffect cell growth and elongation, as well as cotton fibercharacteristics. The identified genes are summarized in Table 7,hereinbelow.

TABLE 7 Summary of genes affecting cell growth and elongation and cottonfiber characteristics Polynucleotide Polypeptide Serial No Gene NameCluster Name Organism SEQ ID NO: SEQ ID NO: 1 CTF165 AI054735 cotton 1130 2 CTF167 AI725458 cotton 2 131 3 CTF101 AI729321 cotton 3 132 4CTF110 AI725814 cotton 4 133 5 CTF111 TG_AI726275 cotton 5 134 6 CTF113AI727515 cotton 6 135 7 CTF124 AI726129 cotton 7 136 8 CTF135 AI727537cotton 8 137 9 CTF162 CO117674 cotton 9 138 10 CTF166 CO095695 cotton 10139 11 CTF169 AI725762 cotton 11 140 12 CTF172 AW186826 cotton 12 141 13CTF173 AI730906 cotton 13 142 14 CTF175 AW187393 cotton 14 143 15 CTF176BE053309 cotton 15 144 16 CTF177 BF269648 cotton 16 145 17 CTF178BF271992 cotton 17 146 18 CTF121 AI731653 cotton 18 147 19 CTF126BF275672 cotton 19 148 20 CTF130 AI725540 cotton 20 149 21 CTF131AI725631 cotton 21 150 22 CTF132 AI726672 cotton 22 151 23 CTF133AI725569 cotton 23 152 24 CTF134 BQ404679 cotton 24 153 25 CTF144AI726469 cotton 25 154 26 CTF146 AI730537 cotton 26 155 27 CTF150AI725910 cotton 27 156 28 CTF155 CA992741 cotton 28 157 29 CTF157BQ405530 cotton 29 158 30 CTF158 CO071210 cotton 30 159 31 CTF159CO096649 cotton 31 160 32 CTF161 CO102097 cotton 32 161 33 CTF163AW187222 cotton 33 162 34 CTF164 DV849461 cotton 34 163 35 CTF168AI725617 cotton 35 164 36 CTF170 AI727242 cotton 36 165 37 CTF171AI727506 cotton 37 166 38 CTF174 AW186645 cotton 38 167 39 CTF180BG440663 cotton 39 168 40 CTF181 BF276183 cotton 40 169 41 CTF182BQ402540 cotton 41 170 42 CTF183 BQ404247 cotton 42 171 43 CTF184BQ408268 cotton 43 172 44 CTF185 BQ410590 cotton 44 173 45 CTF186BQ412432 cotton 45 174 46 CTF187 CO080116 cotton 46 175 47 CTF188CO087604 cotton 47 176 48 CTF189 CO087969 cotton 48 177 49 CTF190CO108798 cotton 49 178 50 CTF191 CO109429 cotton 50 179 51 CTF192CO121056 cotton 51 180 52 CTF193 CO493025 cotton 52 181 53 CTF194DN758069 cotton 53 182 54 CTF195 DT459383 cotton 54 183 55 CTF196DT555914 cotton 55 184 56 CTF197 DT564706 cotton 56 185 57 CTF199AI054474 cotton 57 186 58 CTF200 AI054549 cotton 58 187 59 CTF201AI055034 cotton 59 188 60 CTF202 AI725366 cotton 60 189 61 CTF203AI725561 cotton 61 190 62 CTF204 AI725564 cotton 62 191 63 CTF205AI725800 cotton 63 192 64 CTF206 AI725842 cotton 64 193 65 CTF207AI725955 cotton 65 194 66 CTF208 AI726722 cotton 66 195 67 CTF209AI726995 cotton 67 196 68 CTF210 AI727277 cotton 68 197 69 CTF211DR457681 cotton 69 198 70 CTF212 AI727568 cotton 70 199 71 CTF213AI727795 cotton 71 200 72 CTF214 BF_269744 cotton 72 201 73 CTF215AI729467 cotton 73 202 74 CTF216 AI729616 cotton 74 203 75 CTF217AI730004 cotton 75 204 76 CTF218 AI730197 cotton 76 205 77 CTF219AI730262 cotton 77 206 78 CTF220 AI730418 cotton 78 207 79 CTF221AI730490 cotton 79 208 80 CTF222 AI730776 cotton 80 209 81 CTF223AI731861 cotton 81 210 82 CTF224 AW186914 cotton 82 211 83 CTF225AW187127 cotton 83 212 84 CTF226 BE052628 cotton 84 213 85 CTF227BE053126 cotton 85 214 86 CTF229 BF272961 cotton 86 215 87 CTF230BF274664 cotton 87 216 88 CTF231 BF274983 cotton 88 217 89 CTF232BF275498 cotton 89 218 90 CTF233 BF276821 cotton 90 219 91 CTF234BG440416 cotton 91 220 92 CTF235 BG440584 cotton 92 221 93 CTF236BG442540 cotton 93 222 94 CTF237 BG443240 cotton 94 223 95 CTF238BG447110 cotton 95 224 96 CTF239 CO070299 cotton 96 225 97 DY000718canola 97 226 98 MDL28470M000422 castorbean 98 227 99 CV263160 poplar 99228 100 CA013415 barley 100 229 101 CD820239 canola 101 230 102 AW222076tomato 102 231 103 MDL28708M000182 castorbean 103 232 104 BI129045poplar 104 233 105 AI773326 tomato 105 234 106 EG658665 castorbean 106235 107 BP923230 poplar 107 236 108 CN520627 poplar 108 237 109 BQ468862barley 109 238 110 MDL29933M001398 castorbean 110 239 111 CV228068poplar 111 240 112 CD208850 sorghum 112 241 113 DY005814 canola 113 242114 MDL29637M000752 castorbean 114 243 115 AI161767 poplar 115 244 116BG131373 tomato 116 245 117 EG697134 castorbean 117 246 118 BG125154tomato 118 247 119 MDL29806M000954 castorbean 119 248 120 BI124474poplar 120 249 121 BU831288 poplar 121 250 122 AW039858 tomato 122 251123 EG664483 castorbean 123 252 124 BI127105 poplar 124 253 125 BU893422poplar 125 254 126 CD822731 canola 126 255 127 DY029904 b_oleracea 127256 128 AW441747 tomato 128 257 129 MDL29706M001328 castorbean 129 258Table 7: Summary of genes affecting cell growth and elongation andcotton fiber characteristics

Polypeptides with significant homology to the identified cotton fiberimproving genes, which are expected to serve the same function as theidentified genes, have been identified from the databases using BLASTsoftware (Table 8).

TABLE 8 Significantly homologous polypeptides to the cotton improvinggenes Nucleotide Polypeptide Homology SEQ ID SEQ ID to SEQ ID % NO:Cluster name Organism NO: NO Identity Algorithm 259 AU223627_T1 apple536 148 86 tblastn 260 AU223627_T2 apple 537 148 86 tblastn 261CN444690_T1 apple 538 186 89 tblastn 262 CN488685_T1 apple 539 152 92tblastn 263 CN488848_T1 apple 540 148 86 tblastn 264 CN579093_T1 apple541 152 91 tblastn 265 CN945045_T1 apple 542 186 89 tblastn 266CO416177_T1 apple 543 187 89 tblastn 267 CV044307_T1 apricot 544 148 90tblastn 268 CV044352_T1 apricot 545 148 91 tblastn 269 DR920252_T1aquilegia 546 224 87 tblastn 270 DR930905_T1 aquilegia 547 186 88tblastn 271 DR941117_T1 aquilegia 548 184 91 tblastn 272 AT1G21720_T1arabidopsis 549 152 90 tblastn 273 AT1G77440_T1 arabidopsis 550 152 90tblastn 274 AT3G07410_T1 arabidopsis 551 230 91 tblastn 275 AT3G46000_T1arabidopsis 552 148 85 tblastn 276 AT3G46010_T1 arabidopsis 553 148 86tblastn 277 AT3G46010_T2 arabidopsis 553 148 86 tblastn 278 AT3G46010_T3arabidopsis 554 148 86 tblastn 279 AT3G46010_T4 arabidopsis 554 148 86tblastn 280 AT4G18800_T1 arabidopsis 555 186 88 tblastn 281 AT5G04040_T1arabidopsis 556 226 93 tblastn 282 AT5G45750_T1 arabidopsis 557 186 89tblastn 283 AT5G59890_T1 arabidopsis 558 148 85 tblastn 284 AM061591_T1b_oleracea 559 148 89 tblastn 285 DY013953_T1 b_oleracea 560 148 90tblastn 286 DY026130_T1 b_oleracea 561 148 85 tblastn 287 DY026624_T1b_oleracea 562 148 89 tblastn 288 DY027267_T1 b_oleracea 563 148 85tblastn 289 DY027503_T1 b_oleracea 564 148 90 tblastn 290 DY027503_T2b_oleracea 564 148 90 tblastn 291 DY027857_T1 b_oleracea 565 152 90tblastn 292 DY028163_T1 b_oleracea 566 148 85 tblastn 293 BG543077_T1b_rapa 567 148 85 tblastn 294 BG543272_T1 b_rapa 568 148 90 tblastn 295BG544963_T1 b_rapa 569 148 90 tblastn 296 BQ790771_T1 b_rapa 570 242 98tblastn 297 CO749582_T1 b_rapa 571 148 89 tblastn 298 CX272524_T1 b_rapa572 148 85 tblastn 299 L38533_T1 b_rapa 573 230 94 tblastn 300DN239338_T1 banana 574 148 87 tblastn 301 ES432595_T1 banana 575 152 87tblastn 302 AL501359_T1 barley 576 152 85 tblastn 303 AL509680_T1 barley577 152 85 tblastn 304 DY324442_T1 basilicum 578 152 90 tblastn 305CD811679_T1 canola 579 148 90 tblastn 306 CD812137_T1 canola 580 148 85tblastn 307 CD812887_T1 canola 581 148 85 tblastn 308 CD814124_T1 canola582 148 90 tblastn 309 CD814355_T1 canola 583 148 85 tblastn 310CD818629_T1 canola 584 148 85 tblastn 311 CD818688_T1 canola 585 148 90tblastn 312 CD819087_T1 canola 586 148 89 tblastn 313 CD819123_T1 canola587 152 90 tblastn 314 CD821129_T1 canola 588 148 89 tblastn 315CD824095_T1 canola 589 148 89 tblastn 316 CD824392_T1 canola 590 152 89tblastn 317 CD829819_T1 canola 591 148 85 tblastn 318 CN727283_T1 canola592 148 85 tblastn 319 CN729295_T1 canola 593 148 85 tblastn 320CN737714_T1 canola 594 152 90 tblastn 321 DY007433_T1 canola 595 186 86tblastn 322 DY011922_T1 canola 596 152 88 tblastn 323 DY020991_T1 canola597 186 86 tblastn 324 EE454178_T1 canola 598 152 89 tblastn 325H07822_T1 canola 599 148 90 tblastn 326 EE255551_T1 castorbean 600 14894 tblastn 327 EE258555_T1 castorbean 601 224 88 tblastn 328 EE258555_T2castorbean 602 224 88 tblastn 329 EE259859_T1 castorbean 603 152 92tblastn 330 EG662102_T1 castorbean 604 186 95 tblastn 331MDL28966M000533_T1 castorbean 605 184 91 tblastn 332 MDL29646M001115_T1castorbean 606 139 85 tblastn 333 T14887_T1 castorbean 607 148 88tblastn 334 EE488259_T1 cherry 608 148 85 tblastn 335 BQ623399_T1 citrus609 148 91 tblastn 336 BQ624187_T1 citrus 610 152 92 tblastn 337BQ624753_T1 citrus 611 148 92 tblastn 338 CB291434_T1 citrus 612 186 94tblastn 339 CF505092_T1 citrus 613 224 89 tblastn 340 CF505190_T1 citrus614 148 92 tblastn 341 CF833473_T1 citrus 615 152 92 tblastn 342CF838037_T1 citrus 616 187 91 tblastn 343 DY261108_T1 citrus 617 173 86tblastn 344 DV667368_T1 coffea 618 148 93 tblastn 345 DV667647_T1 coffea619 148 93 tblastn 346 DV668122_T1 coffea 620 231 90 tblastn 347DV671720_T1 coffea 621 148 87 tblastn 348 DV673964_T1 coffea 622 152 94tblastn 349 DV684181_T1 coffea 623 186 91 tblastn 350 AI725473_T1 cotton624 187 89 tblastn 351 AI725715_T1 cotton 625 186 96 tblastn 352AI725715_T2 cotton 626 186 96 tblastn 353 AI725715_T3 cotton 627 186 98tblastn 354 AI726232_T1 cotton 628 186 95 tblastn 355 AI726275_T1 cotton629 134 99 tblastn 356 AI726544_T1 cotton 630 148 89 tblastn 357AI726815_T1 cotton 631 148 90 tblastn 358 AI726907_T1 cotton 632 147 97tblastn 359 AI727140_T1 cotton 633 148 97 tblastn 360 AI727282_T1 cotton634 155 97 tblastn 361 AI727959_T1 cotton 635 148 100 tblastn 362AI728713_T1 cotton 636 148 93 tblastn 363 AI730512_T1 cotton 637 157 96tblastn 364 AI731512_T1 cotton 638 184 95 tblastn 365 AI731769_T1 cotton639 152 97 tblastn 366 AI732019_T1 cotton 640 137 97 tblastn 367AW186735_T1 cotton 641 224 92 tblastn 368 BE051989_T1 cotton 642 157 97tblastn 369 BE053515_T1 cotton 643 148 90 tblastn 370 BG441743_T1 cotton644 139 85 tblastn 371 BG445675_T1 cotton 645 153 97 tblastn 372BQ404948_T1 cotton 646 184 97 tblastn 373 CO076074_T2 cotton 647 225 88tblastn 374 CO090129_T1 cotton 648 148 89 tblastn 375 CO107228_T1 cotton649 160 90 tblastn 376 CO117171_T1 cotton 650 148 92 tblastn 377DT563255_T1 cotton 651 186 94 tblastn 378 DW495789_T1 cotton 652 149 96tblastn 379 CV478457_T1 flax 653 148 89 tblastn 380 BM436339_T1 grape654 148 95 tblastn 381 BM436339_T2 grape 654 148 95 tblastn 382BQ794373_T1 grape 655 173 85 tblastn 383 BQ796448_T1 grape 656 148 94tblastn 384 BQ796448_T2 grape 656 148 94 tblastn 385 BQ796638_T1 grape657 152 93 tblastn 386 BQ797077_T1 grape 658 148 93 tblastn 387BQ797077_T2 grape 658 148 93 tblastn 388 BQ797077_T3 grape 658 148 93tblastn 389 BQ797077_T4 grape 658 148 93 tblastn 390 CB035843_T1 grape659 224 88 tblastn 391 CB911305_T1 grape 660 186 93 tblastn 392CB916297_T1 grape 661 184 91 tblastn 393 CF373264_T1 grape 662 186 86tblastn 394 CN545526_T1 grape 663 139 85 tblastn 395 EE106378_T1 grape664 132 86 tblastn 396 BJ554624_T1 ipomoea 665 148 92 tblastn 397BJ555556_T1 ipomoea 666 139 86 tblastn 398 BJ556366_T1 ipomoea 667 15292 tblastn 399 BJ556502_T1 ipomoea 668 186 88 tblastn 400 BJ559892_T1ipomoea 669 148 94 tblastn 401 BJ563588_T1 ipomoea 670 224 88 tblastn402 CB330087_T1 ipomoea 671 173 85 tblastn 403 CJ738141_T1 ipomoea 672231 91 tblastn 404 EE875053_T1 ipomoea 673 148 94 tblastn 405DW043786_T1 lettuce 674 148 87 tblastn 406 DW049988_T1 lettuce 675 22486 tblastn 407 DW052597_T1 lettuce 676 148 87 tblastn 408 DW052758_T1lettuce 677 152 90 tblastn 409 DW053430_T1 lettuce 678 152 92 tblastn410 DW053430_T2 lettuce 678 152 92 tblastn 411 DW074782_T1 lettuce 679148 86 tblastn 412 DW081477_T1 lettuce 680 152 91 tblastn 413DW081477_T2 lettuce 680 152 91 tblastn 414 DW084530_T1 lettuce 681 14886 tblastn 415 DW135542_T1 lettuce 682 152 92 tblastn 416 BG662283_T1lotus 683 152 92 tblastn 417 BI417319_T1 lotus 684 152 93 tblastn 418AI586912_T1 maize 685 152 85 tblastn 419 AI714711_T1 maize 686 152 87tblastn 420 AI920333_T1 maize 687 184 91 tblastn 421 AW054435_T1 maize688 152 85 tblastn 422 AW056991_T1 maize 689 152 85 tblastn 423BM500177_T1 maize 690 186 86 tblastn 424 CD945757_T1 maize 691 186 86tblastn 425 DQ245781_T1 maize 692 148 85 tblastn 426 DQ245820_T1 maize693 148 85 tblastn 427 AA661031_T1 medicago 694 186 85 tblastn 428AL370167_T1 medicago 695 152 89 tblastn 429 AW686071_T1 medicago 696 14886 tblastn 430 AW687059_T1 medicago 697 152 92 tblastn 431 BE205479_T1medicago 698 132 86 tblastn 432 AJ827186_T1 peach 699 148 90 tblastn 433AJ827260_T1 peach 700 148 91 tblastn 434 AJ872529_T1 peach 701 152 92tblastn 435 BU039190_T1 peach 702 148 85 tblastn 436 CD037927_T1 peanut703 148 94 tblastn 437 CX018158_T1 peanut 704 152 95 tblastn 438BM064776_T1 pepper 705 152 90 tblastn 439 CA523467_T1 pepper 706 148 91tblastn 440 AF183903_T1 petunia 707 148 89 tblastn 441 AF183904_T1petunia 708 148 92 tblastn 442 DW177184_T1 petunia 709 139 87 tblastn443 CO730856_T1 pineapple 710 148 88 tblastn 444 CO731353_T1 pineapple711 148 87 tblastn 445 CO731804_T1 pineapple 712 186 89 tblastn 446DT338785_T1 pineapple 713 148 89 tblastn 447 AA739732_T1 pine 714 152 87tblastn 448 CO363003_T1 pine 715 152 87 tblastn 449 AI161898_T1 poplar716 148 94 tblastn 450 AI161898_T2 poplar 717 148 93 tblastn 451AI161898_T3 poplar 718 148 94 tblastn 452 AI161961_T1 poplar 719 148 94tblastn 453 AI161961_T2 poplar 719 148 94 tblastn 454 AI161961_T3 poplar720 148 92 tblastn 455 AI161961_T4 poplar 720 148 92 tblastn 456AI162478_T1 poplar 721 152 87 tblastn 457 AI162845_T1 poplar 722 186 94tblastn 458 BI122785_T1 poplar 723 148 90 tblastn 459 BU813699_T1 poplar724 148 89 tblastn 460 BU813699_T2 poplar 724 148 89 tblastn 461BU836906_T1 poplar 725 186 93 tblastn 462 BU875572_T1 poplar 726 139 85tblastn 463 BU875572_T2 poplar 726 139 85 tblastn 464 CV228249_T1 poplar727 224 88 tblastn 465 CV237204_T1 poplar 728 152 86 tblastn 466CV237204_T2 poplar 728 152 86 tblastn 467 BE344367_T1 potato 729 148 91tblastn 468 BG593676_T1 potato 730 245 89 tblastn 469 BG597337_T1 potato731 148 90 tblastn 470 BG598410_T1 potato 732 247 97 tblastn 471BG598410_T2 potato 733 247 97 tblastn 472 BG888799_T1 potato 734 152 88tblastn 473 BQ118661_T1 potato 735 139 85 tblastn 474 BQ118661_T2 potato736 139 85 tblastn 475 BQ516531_T1 potato 737 148 91 tblastn 476CK851382_T1 potato 738 148 91 tblastn 477 CN212590_T1 potato 739 251 93tblastn 478 CN212590_T2 potato 739 251 93 tblastn 479 AF327517_T1 rice740 186 86 tblastn 480 BI118688_T1 rice 741 152 85 tblastn 481BI795939_T1 rice 742 148 85 tblastn 482 U38037_T1 rice 743 152 85tblastn 483 U38037_T2 rice 743 152 85 tblastn 484 BQ104946_T1 rose 744148 92 tblastn 485 EC586289_T1 rose 745 186 89 tblastn 486 EC588463_T1rose 746 148 88 tblastn 487 BU669008_T1 sesame 747 148 94 tblastn 488AW285608_T1 sorghum 748 152 86 tblastn 489 BE592644_T1 sorghum 749 15287 tblastn 490 BE595956_T1 sorghum 750 184 91 tblastn 491 AW349054_T1soybean 751 186 86 tblastn 492 AW349285_T1 soybean 752 148 87 tblastn493 AW349636_T1 soybean 753 152 92 tblastn 494 AW569132_T1 soybean 754152 92 tblastn 495 BE352761_T1 soybean 755 187 89 tblastn 496BE659353_T1 soybean 756 139 85 tblastn 497 BE659353_T2 soybean 756 13985 tblastn 498 BE661354_T1 soybean 757 148 89 tblastn 499 BI969429_T1soybean 758 152 93 tblastn 500 BI971168_T1 soybean 759 148 88 tblastn501 CA852085_T1 soybean 760 186 86 tblastn 502 CD390653_T1 soybean 761148 93 tblastn 503 AF051246_T1 spruce 762 152 87 tblastn 504 AF051246_T2spruce 762 152 87 tblastn 505 CA069331_T1 sugarcane 763 152 87 tblastn506 CA106361_T1 sugarcane 764 152 86 tblastn 507 CA118153_T1 sugarcane765 186 86 tblastn 508 CD851311_T1 sunflower 766 152 90 tblastn 509CD851311_T2 sunflower 766 152 90 tblastn 510 CX943625_T1 sunflower 767148 85 tblastn 511 DY914967_T1 sunflower 768 152 90 tblastn 512DN772748_T1 thellungiella 769 148 89 tblastn 513 BP130889_T1 tobacco 770247 86 tblastn 514 BP136053_T1 tobacco 771 152 89 tblastn 515BP136053_T2 tobacco 771 152 89 tblastn 516 CV017679_T1 tobacco 772 14890 tblastn 517 CV017893_T1 tobacco 773 148 92 tblastn 518 CV019967_T1tobacco 774 148 90 tblastn 519 CV020081_T1 tobacco 775 224 86 tblastn520 CV021812_T1 tobacco 776 148 89 tblastn 521 EB424751_T1 tobacco 777148 87 tblastn 522 EB426768_T1 tobacco 778 148 92 tblastn 523BG124262_T1 tomato 779 148 90 tblastn 524 BG126286_T1 tomato 780 148 91tblastn 525 BG127143_T1 tomato 781 152 88 tblastn 526 BG133022_T1 tomato782 224 86 tblastn 527 BG629194_T1 tomato 783 148 89 tblastn 528BG643389_T1 tomato 784 186 88 tblastn 529 BE398818_T1 wheat 785 152 86tblastn 530 BE403180_T1 wheat 786 152 85 tblastn 531 BE490465_T1 wheat787 152 85 tblastn 532 BF202079_T1 wheat 788 186 86 tblastn 533BF484998_T1 wheat 789 229 93 tblastn 534 BQ806763_T1 wheat 790 152 85tblastn 535 CA610895_T1 wheat 791 152 86 tblastn Table 8: Significantlyhomologous polypeptides to the cotton improving genes.

Example 5 Cloning of the Selected Genes in a Binary Vector UnderConstitutive Regulation and Recombinant Expression of Same

Bioinformatics Analysis

Open Reading Frame (ORF) Analysis

Gene sequences of the present study were analyzed for ORFs using GeneRunner software version 3.05 [Hasting Software, Inc: World Wide Web(dot) generunner (dot) com/] ORFs of each gene were compared to Genbankdatabase, using Blast [World Wide Web (dot) ncbi (dot) nlm (dot) nih(dot) gov/BLAST/]. By comparing to the highest homologous ORFs, theposition of the ATG initiation codon was determined. All the sequencesdescribed herein were shown to have a predicted full length ORF and toinclude the predicted ATG starting codon.

Experimental Procedures and Results

Cloning into the pPI/pGI Expression Vector

For cloning the genes of the present study, total RNAs from the variousdevelopmental stages of fiber producing cells was extracted, using HotBorate RNA Extraction from Cotton Tissue grown in Rehovot, Israel,according to World Wide Web (dot) eeob (dot) iastate (dot)edu/faculty/WendelJ/rnaextraction (dot) html. Complementary DNA (cDNA)molecules were produced from mRNA using M-MuLV reverse-transcriptase(RT) enzyme (Roche) and Ti6NN DNA primer, following protocol provided bythe manufacturer. cDNA amplification was done for 19 genes, out of thesequences above, namely CTF clones: CTF101, CTF110, CTF111, CTF113,CTF124, CTF132, CTF135, CTF162, CTF165, CTF166, CTF167, CTF169, CTF171,CTF172, CTF173, CTF175, CTF176, CTF177 and CTF178 (SEQ ID NOs:1-17, 22and 37; Table 7 hereinabove) by PCR using PFU proof reading DNApolymerase enzyme [Promega, World Wide Web (dot) promega (dot)com/pnotes/68/7381_07/7381_07 (dot) html] following the protocolprovided by the manufacturer. Primers for each gene were designed tospan the full ORF. Additional restriction endonuclease sites were addedto the 5′ end of each primer to facilitate further cloning of the CTFsto the binary vector (pPI). Table 9 below, lists the primers used forcloning each of the genes:

TABLE 9 Primers used to clone each of the genes upstream downstream CTFForward Primer/SEQ Reverse Primer/SEQ restriction restriction No. ID NO:ID NO: site site CTF101 CACCCGGGACCACCATC GAGAGCTCTCCAAAATTGAC Sma SacAAACCACATCC/801 ACACCAGG/802 CTF110 AACCCGGGTTCCCTTTCCCACCCGGGTACCTAAAGTTG Sma Sma AAGCTTCAGC/803 CAGCTTGC/804 CTF111TTCCCGGGTTGCCTTTTT CAGAGCTCTTGTTTATGAATC Sma Sac GTCATTTCCC/805CACTTTGGG/806 CTF113 GACCCGGGAAACGATGG CAGAGCTCTTGGAATTGAAA Sma SacAGGATCTTGCC/807 TGTCATTACAGAG/808 CTF124 TTCCCGGGCACTCTTCATTTGAGCTCTGGATTTCTGAAA Sma Sac TCCTCACCTACTC/809 ACAACCG/810 CTF132AACCCGGGCACCACCTC TTGAGCTCTGCTCTTATATCA Sma Sac CACTCACCTTC/811TGTGAAGGC/812 CTF135 CACCCGGGAACTCTTCA ACGAGCTCAGCTAGATAAAT Sma SacAGACCATTCGAC/813 CACAACCATCC/814 CTF162 TGCCCGGGTTCAGCGTTGTGAGCTCTGCCTGACACATT Sma Sac CGAATCCATG/815 GACATGC/816 CTF165CTCCCGGGTTTGAAGCT TTGAGCTCAGGGACCAATTT Sma Sac CAGGAACTAATGG/817GTTGCCA/818 CTF166 ACGATATCAAGAATCCG CTGAGCTCGGAAGTAAATTT EcoRV SacACCCGGTAAC/819 GGACACTCG/820 CTF167 AACCCGGGCCCTAAGATTGGAGCTCAATAATCATGTG Sma Sac GACAAACCAAGA/821 GCAGTAGTTTG/822 CTF169GACCCGGGAAACATGGA CGGAGCTCAAAAGCATTCAG Sma Sac AGGAGACGATG/823AACAACCAG/824 CTF171 AGCCCGGGAAACATGTT AGGAGCTCAATTACAACCAA Sma SacTGCAGGAGATCAG/825 AGGTTAACCC/826 CTF172 ACCCCGGGGAGCTCTGGCTCCCGGGTAGACTTGTAGT Sma Sma ATACAGTTAAGAATC/827 AAAGCATGTATCC/828CTF173 ATCCCGGGAGTTAACTG TCGAGCTCAACAACTATACC Sma SacGTCTCTTCTGATGTC/829 AGTCATTGCTTC/830 CTF175 AGGATATCTTTCGATCAGCGAGCTCGTAGTGACGTCA EcoRV Sac CCGTGATGGC/831 CCGGTTC/832 CTF176GACCCGGGAGACACACA AAGAGCTCTATCACTTACATC Sma Sac AAGCGAGAAGG/833CTAGGCAGC/834 CTF177 TTCCCGGGTCTGGCTTG AAGAGCTCGCATTGAACTTC Sma SacAAAATGGTGTG/835 ATCATCTGTAAG/836 CTF178 CGCCCGGGTTTTTCCAACACCCGGGCCAATAAACAAT Sma Sma CTAAGGTTAGGC/837 AGCACTGC/838

The resultant PCR blunt ended products were purified using PCRPurification Kit (Qiagen, Germany), digested with the appropriaterestriction endonucleases (Roche) and cloned into the pPI or pGI binaryvector (FIG. 1), while replacing the existing GUS reporter gene. pPI isa modified version of pBI101.3 (Clontech, Accession No. U12640). pPI wasconstructed by inserting a synthetic poly-(A) signal sequence, whichoriginated from pGL3 Basic plasmid vector (Promega, GenBank AccessionNo. U47295, where the synthetic poly-(A) signal sequence is locatedbetween nucleotides 4658-4811), into the HindIII restriction site ofpBI101.3 [while reconstituting the HindIII site, downstream to thepoly-(A) insert], to avoid the possibility of read-through effect of theupstream Nos-promoter. In some cases the backbone binary plasmid usedwas pGI which is similar to pPI but the GUS gene was replaced by theGUS-Intron gene (Vancanneyt. G, et al MGG 220, 245-50, 1990). To replacethe GUS/GUS-Intron gene with each one of the CT genes in the pPI/pGIbinary vector, pPI/pGI was digested with the appropriate restrictionenzymes [5′ prime restriction enzyme is either SmaI or XbaI and 3′ primerestriction enzyme is either SacI or EcoRV (Roche—using the protocolprovided by the manufacturer)]. Open binary vector was purified usingPCR Purification Kit (Qiagen, Germany). 5-75 ng of PCR product of eachof the CTF genes and 100 ng of open pPI/pGI plasmid vector were ligatedin 10 μL ligation reaction volume using T4 DNA ligase enzyme (Roche),following the protocol provided by the manufacturer. Ligation productswere introduced into E. coli cells.

Recombinant Expression in Bacteria

60 μl of E. coli, strain DH5-α competent cells (about 10⁹ cells/ml) weretransformed using 1 μl of ligation reaction mixture by electroporation,using a MicroPulser electroporator (Biorad), 0.2 cm cuvettes (Biorad)and EC-2 electroporation program (Biorad). E. coli cells were grown on0.8 ml LB liquid medium at 37° C. for 1 hour and 0.2 ml of the cellsuspension were plated on LB-agar plates supplemented with theantibiotics kanamycin 50 mg/L (Sigma). Plates were then incubated at 37°C. for 16 hours. Bacteria colonies were grown and expression wasconfirmed by PCR amplification using primers which were designed to spanthe inserted sequence in the binary vector. Primers used for DNAamplification of the inserts in the pPI binary vector were:5′-GGTGGCTCCTACAAATGCCATC-3′ (forward, SEQ ID NO:839) and5′-AAGTTGGGTAACGCCAGGGT-3′ (reverse, SEQ ID NO:840).

PCR products were separated on 1.5% agarose gels and product sizes wereestimated by comparing to DNA ladder (MBI Fermentas). PCR products withthe predicted size were sequenced using the same primers previously usedfor PCR amplification (See Table 9, above).

Additional primers, which were designed based on the sequence of eachgene insert, were used to complete the sequencing of the full length ORFinsert.

Sequencing of the inserted sequence was performed to verify that theclones were introduced in the right orientation, and to eliminate thepossibility that sequence errors were included during PCR amplification.DNA sequences were determined using ABI 377 sequencer (AmershamBiosciences Inc). The cloned cDNA sequences of 17 cotton genes areprovided (SEQ ID NOs:906-922), as well as their deduced amino acidsequences (SEQ ID NOs:923-939). In most cases, minute changes were foundbetween the bioinformatically predicted sequence and the cloned ones,probably due to allelic variations and sequence quality of the ESTs inthe database.

Into each one of the 19 pPI/pGI binary constructs harboring the CTFgenes, the constitutive Cauliflower Mosaic Virus 35S promoter wascloned.

Cauliflower Mosaic Virus 35S promoter sequence (SEQ ID NO:841),originated from the pBI121 vector (Clontech, GenBank Accession No.AF485783) was cloned by digesting the pBI121 vector with the restrictionendonucleases HindIII and BamHI (Roche) and ligated into the binaryconstructs, digested with the same enzymes.

Example 6 Agrobacterium Transformation of Binary Plasmids Harboring theGenes of Interest and Expression in Tomato Plants

In a previous study the present inventors have demonstrated thepotential of using tomato seed hair as a model for cotton fiber (PCTIL2005/000627). Thus, to demonstrate the effect of the isolated fiberimproving genes of the present study on fiber growth, tomato plants weretransformed with the binary vectors comprising the isolated cotton genesunder the transcriptional regulation of the 35S promoter. Each of thenineteen binary constructs, comprising the 35S promoter upstream of eachof the CTFs genes was transformed into tomato plants via Agrobacteriumtumefacience transformation, as follows.

Experimental Procedures and Results

Transformation of the Binary Constructs Comprising the 35S PromoterUpstream of the CTF Genes into Tomato Plants Via Agrobacteriumtumefacience

60 μl of Agrobacterium tumefaciens GV301 or LB4404 competent cells(about 10⁹ cells/ml) were transformed with 20 ng of binary plasmid viaelectroporation, using a MicroPulser electroporator (Biorad), 0.2 cmcuvettes (Biorad) and EC-2 electroporation program (Biorad).

Agrobacterium cells were grown on 0.8 ml LB liquid medium at 28° C. for3 hours and 0.2 ml of the cell suspension were plated on LB-agar platessupplemented with the antibiotics gentamycin 50 mg/L (for Agrobacteriumstrains GV301) or streptomycin 300 mg/L (for Agrobacterium strainLB4404) and kanamycin 50 mg/L (Sigma). Plates were then incubated at 28°C. for 48 hours. Agrobacterium colonies were grown and PCR amplificationwas performed on Agrobacterium cells, using primers which were designedto span the inserted sequence in the binary vector.

Primers used for PCR amplification were: 5′-GGTGGCTCCTACAAATGCCATC-3′(forward, SEQ ID NO:839) and 5′-AAGTTGGGTAACGCCAGGGT-3′ (reverse, SEQ IDNO:840).

PCR products were separated on 1.5% agarose gels and product sizes weredetermined by comparing to DNA ladder (MBI Fermentas). PCR products withthe predicted size were sequenced using the primers which were used forthe PCR amplification. Sequencing of the inserted sequence was performedusing the ABI 377 sequencer (Amersham Biosciences Inc.) in order toverify that the right clones were introduced into the Agrobacteriumcells.

Transformation of Micro-Tom Tomato Plants with Putative Cotton Genes

Tomato (Lycopersicon esculentum, var MicroTom) transformation andcultivation of transgenic plants was effected according to Curtis et al.1995, and Meissner et. al. 2000, with slight modifications.

Example 7 Growth of MicroTom Transformed Plants and PhenotypeCharacterizations

Experimental Procedures

Producing Transgenic Tomato Plants

Plants were transformed as described in Example 6, above. Followingtransformation, T1 MicroTom tomato plants were grown in a mix thatcontained in 1000 ml pots until fruit set. The tomato seed hair lengthwas measured.

Experimental Results

The micro-Tom tomato seeds (T2, origin from T1 plants), which carry theputative cotton genes following the transformation with Agrobacteriumcells carrying the CTF genes, were analyzed (Table 10, hereinbelow).Least Sq mean are the predicted values corresponding to some combinationof levels, after setting all the other factors to some neutral value(JMP™ V5). For each gene, the overall mean influence of the gene (leastSq mean), and the event that gave the best results (Best event), whichcan pinpoint on the potential of the gene, is shown in Table 10,hereinbelow. we demonstrate the results of. The letters “A, B and C”refer to genes that are significantly different from each other atP<0.05.

TABLE 10 Analysis of Micro-Tom tomato seeds carrying the putative cottongenes Number Signif- % of of icant Best inde- Least (t-Test % eventpendent Sq compare compare Best compare Gene events Mean to wt) to wtevent to wt CTF165 10 33.8 A 21 40.0 43 CTF172 10 33.2 A 19 36.3 30CTF167 9 32.5 A 16 42.7 ^(a) 53 Expansin 8 32.0 A 15 35.0 25 (SEQ ID NO:905) CTF178 7 31.9 A 14 38.3 37 CTF135 8 30.8 A 10 37.3 34 CTF124 9 30.0B 7 31.7 13 CTF169 11 29.9 B 7 39.3 ^(b) 41 CTF166 9 29.8 B 7 36.0 ^(b)29 CTF111 8 28.8 B 3 35.0 ^(b) 25 WT — 27.9 B 0 CTF113 7 27.0 B −3 31.011 CTF110 9 27.0 B −4 39.0 ^(b) 40 CT101 7 23.4 C −16 26.0 −7 Table 10:Analysis of Micro-Tom tomato seeds (T2, origin from T1 plants) carryingthe putative cotton genes is presented. ^(a) Best event wassignificantly higher than expansin best event; ^(b) Best event wassignificantly higher than WT.

Example 8 Isolation, Cloning and Analysis of Cotton Fiber SpecificPromoters

One of the important requirements for engineered plants is to activatethe right gene in the right place. In order to improve fiber quality, abasic requirement for engineered plants is a promoter providing anexpression pattern that is appropriate for fiber development.Constitutive promoters allow expression of preformed genes in which theeffect of the protein is present continuously throughout the plant. TheCaMV35S promoter from cauliflower mosaic virus is a widely used example.In order to improve cotton fiber quality, it is advantageous to combinetarget genes with fiber specific promoter, to avoid influence of thegenes on the cell structure in other cotton tissues, and to activate thegenes at the fiber tissue in the right development stage (initiation,elongation, maturation, fiber constitutive). The present inventors haveselected and cloned the genomic sequence of novel cotton fiberpromoters, as follows.

Experimental Procedures and Results

Cloning of Promoter Sequences of Native Cotton Genes

The desired cotton promoters were chosen based on the expression profileof their encoded native genes.

Expression profiles of the chosen 4 cotton genes CT4 (SEQ ID NO:842),CT9 (SEQ ID NO:843), CT11 (SEQ ID NO:844) and CT74 (SEQ ID NO:845) arepresented in FIGS. 2a -2 d.

The genomic sequence upstream of CT4, CT9, CT11, and CT74 were clonedfrom genomic DNA of cotton (Gossypium barbdanse L. var S5), as follows.

Total genomic DNA was extracted from plant leaf tissues of 4 week oldcultivated cotton plants (Gossypium barbdanse L. var S5), using DNAextraction kit (Dneasy plant mini kit, Qiagen, Germany). For promoterisolation the BD GenomeWalker™ kit (BD Biosciences Clontech) was used.In addition to the 4 restriction enzymes used in the kit, the blunt endrestriction enzymes SmaI, EcoRV and Ecl136II were also used. For eachpromoter, a set of two specific primers were used for the first round:

Primers for CT4 Promoter were as Follows (UP-PCR):

External primer: CT4 GSP_R- 5′-GTGGACCCTGAAACATACTCACCAGC-3′;(SEQ ID NO: 846) Internal (Nested) primer: CT4 GSP_NR-5′-AAGCCATATTGCCAATGTCACTTCCTC-3′; (SEQ ID NO: 847)

For CT4 promoter the library was originated from StuI restrictionenzyme.

The putative promoter sequence of CT4 cloned using the above procedureis set forth by SEQ ID NO:848.

Primers for CT74 Promoter were as Follows (UP-PCR):

External primer: CT74 GSP_R- 5′-GCATGAGGGTCAGGAGCTGGATAGTAG-3′;(SEQ ID NO: 849) Internal (Nested) primer: CT74 GSP_NR-5′-CTTCTTTGCCTCTCCATCTCTGTATGC-3′ (SEQ ID NO: 850)

For CT74 promoter the library was originated from DraI and PvuIIrestriction enzymes.

The putative promoter sequence of CT74 cloned using the above procedureis set forth by SEQ ID NO:851.

Primers for CT11 Promoter were as Follows (UP-PCR):

External primer: CT11 GSP_R- 5′-ACCTGAGGTATTTTGGTAAGAGTTCCG-3′.(SEQ ID NO: 852) Internal (Nested) primer: CT11 GSP_NR-5′-CCAATTCAGCTTTCGGAAAATCACG-3′. (SEQ ID NO: 853)

For CT11 promoter the library was originated from SmaI and StuIrestriction enzymes.

The putative promoter sequence of CT11 cloned using the above procedureis set forth by SEQ ID NO:854.

Primers for CT9 Promoter were as Follows (UP-PCR):

External primer: CT9 GSP_R- 5′-GGCATTTTTAAGATGTGAAACGTCGG-3′.(SEQ ID NO: 855) Internal (Nested) primer: CT9 GSP_NR-5′-GCTCGACTTTGGGTGGACATGTATGTAG-3′. (SEQ ID NO: 856)

For CT9 promoter the library was originated from DraI and SmaIrestriction enzymes.

The putative promoter sequence of CT9 cloned using the above procedureis set forth by SEQ ID NO:857.

PCR products were purified using PCR purification kit (Qiagen) andsequencing of the amplified PCR products was performed, using ABI 377sequencer (Amersham Biosciences Inc).

For cloning the putative promoters and 5′ UTRs, PCR amplification wascarried out using a new set of primers (below) to which 8-12 bpextension that included one restriction site (HindIII, SalI, XbaI,BamHI, or SmaI) on the 5′ end. For each promoter, restriction sites thatdo not exist in the promoter sequence were selected. Moreover, therestriction sites in the primer sequences were designed so the resultantPCR products were cloned into the binary vector pPI or pGI (see Example5 above) in the right orientation, upstream of the GUS reporter gene.

Following are the primers used for promoter and 5′ UTR (P+U)amplification and cloning into pPI.

CT74_1000: CT74-pro-F-H (HindIII): (SEQ ID NO: 858)-5′-ATACAAGCTTGTTGAGGGAGATTGATTTCTTTGG-3′; and CT74-pro-R-SL (SalI):(SEQ ID NO: 859)- 5′-CAAAGTCGACAAGATTGGAAGATGTGTGAGTTGAG-3′. CT74_1400:CT74-pro-F-H-2 (HindIII): (SEQ ID NO: 860)-5′-TGTTAAGCTTGTAAAATCACAGGCTAACTATCACTC-3′; and CT74-pro-R-SL (SalI):.(SEQ ID NO: 859) CT74_1700: CT74_pro_F_H_3 (HindIII): (SEQ ID NO: 861)-5′-GTCGAAGCTTTGGTCTGTCCGGATCACTGTG-3′; and CT74-pro-R-SL (SalI):.(SEQ ID NO: 859) CT4_1000: CT4-pro-F-H (HindIII): (SEQ ID NO: 862)-5′-ACTTAAGCTTGGTAAAACTTCAACTTGCCTTTG-3′; and CT4-pro-R-SL (SalI):(SEQ ID NO: 863)- 5′-CAAAGTCGACTTGCCAATGTCACTTCCTCCC-3′. CT4_1400:CT4_pro_F_H_2 (HindIII): (SEQ ID NO: 864)-5′-CAACAAGCTTAGCATGCCACTTTTCACCATC-3′; and CT4-pro-R-SL (SalI):.(SEQ ID NO: 863) CT11_730: CT11_pro_F_SL(SalI): (SEQ ID NO: 865)-5′-ATATGTCGACATTGAGGCCATTAAAGTTCATC-3′; and CT11_pro_R_Xb (XbaI):(SEQ ID NO: 866)- 5′-CATTCTAGATCTCTTTGATCACTTGCACCTG-3′ CT9_650:CT9_pro_F_H (HindIII): (SEQ ID NO: 867)-5′-TTCGAAGCTTGTCTCCCGTCTAAACTTATCCTG-3′; and CT9_pro_R_SL (SalI):(SEQ ID NO: 868)- 5′-AGGAGTCGACCATGTATGTAGTAATGATAGCAGCTG-3′.

Genomic DNA or the IPCR/UP-PCR product was used as DNA template forPCR-amplification, using the newly designed oligonucleotide primers. PCRproducts were purified (PCR Purification Kit, Qiagen, Germany) anddigested with the restriction sites exist in the primers (Roche,Switzerland). The digested PCR products were re-purified and cloned intothe binary vector pPI/pGI, which was digested with the same restrictionenzymes. PCR product and the open plasmid vector were ligated using T4DNA ligase enzyme (Roche, Switzerland).

Example 9 Transforming Agrobacterium Tumefacience Cells with BinaryVectors Harboring Cotton Fiber Promoters

pPI/pGI Binary vector, including either CT4, CT11, CT9 or CT74 promoter,upstream to the GUS reporter gene were used to transform Agrobacteriumcells.

Experimental Procedures and Results

Transformation of Binary Vectors Including Cotton Fibers Promoters intoAgrobacterium tumefaciens

The binary vectors were introduced to Agrobacterium tumefaciens GV301,or LB4404 competent cells (about 10⁹ cells/ml) by electroporation.Electroporation was performed using a MicroPulser electroporator(Biorad), 0.2 cm cuvettes (Biorad) and EC-2 electroporation program(Biorad). The treated cells were cultured in LB liquid medium at 28° C.for 3 hours, then plated over LB agar supplemented with gentamycin (50mg/L; for Agrobacterium strains GV301) or streptomycin (300 mg/L; forAgrobacterium strain LB4404) and kanamycin (50 mg/L) at 28° C. for 48hours. Agrobacterium colonies which developed on the selective mediawere analyzed by PCR using the primers set forth in SEQ ID NO:869 101F:5′-GCTATGACCATGATTACGCC-3′ and SEQ ID NO:870 GUSREV:5′-CTGCATCGGCGAACTGATCG-3′, which were designed to span the insertedsequence in the pPI/pGI plasmid. The resulting PCR products wereisolated and sequenced, to verify that the correct sequences wereproperly introduced to the Agrobacterium cells.

Example 10 Cotton Fiber Specific Promoters are Expressed in TomatoLeaves and Fruits, and in Arabidopsis and Cotton Plants

To illustrate specific expression in arabidopsis and tomato trichomesand in tomato fruits, GUS staining was performed on transformed plants,as follows.

Experimental Procedures

Transformation of Micro-Tom Tomato Plants with Putative Cotton Promoters

Tomato (Lycopersicon esculentum, var MicroTom) transformation andcultivation of transgenic plants was performed according to Curtis etal. 1995, and Meissner et. al. 2000.

Transformation and Cultivation of Arabidopsis thaliana Plants withPutative Cotton Promoters

Arabidopsis thaliana Columbia plants (T0 plants) were transformed usingthe Floral Dip procedure described by Clough and Bent (1998) and byDesfeux et al. (2000), with minor modifications. Briefly, T0 Plants weresown in 250 ml pots filled with wet peat-based growth mix. The pots werecovered with aluminum foil and a plastic dome, kept at 4° C. for 3-4days, then uncovered and incubated in a growth chamber at 18-24° C.under 16/8 hours light/dark cycles. The T0 plants were ready fortransformation six days prior to anthesis. Single colonies ofAgrobacterium carrying the binary constructs, were cultured in LB mediumsupplemented with kanamycin (50 mg/L) and gentamycin (50 mg/L). Thecultures were incubated at 28° C. for 48 hours under vigorous shakingand then centrifuged at 4,000 rpm for 5 minutes. The pellets comprisingAgrobacterium cells were resuspended in a transformation mediumcontaining half-strength (2.15 g/L) Murashig-Skoog (Duchefa); 0.044 μMbenzylamino purine (Sigma); 112 μg/L B5 Gambourg vitamins (Sigma); 5%sucrose; and 0.2 ml/L Silwet L-77 (OSI Specialists, CT) indouble-distilled water, at pH of 5.7. Transformation of T0 plants waseffected by inverting each plant into an Agrobacterium suspension, suchthat the above ground plant tissue was submerged for 3-5 seconds. Eachinoculated T0 plant was immediately placed in a plastic tray, thencovered with clear plastic dome to maintain humidity and was kept in thedark at room temperature for 18 hours, to facilitate infection andtransformation. Transformed (i.e., transgenic) plants were thenuncovered and transferred to a greenhouse for recovery and maturation.

The transgenic T0 plants were grown in the greenhouse for 3-5 weeksuntil siliques were brown and dry. Seeds were harvested from plants andkept at room temperature until sowing. For generating T1 transgenicplants harboring the genes, seeds collected from transgenic T0 plantswere surface-sterilized by soaking in 70% ethanol for 1 minute, followedby soaking in 5% sodium hypochloride and 0.05% triton for 5 minutes. Thesurface-sterilized seeds were thoroughly washed in sterile distilledwater then placed on culture plates containing half-strengthMurashig-Skoog (Duchefa); 2% sucrose; 0.8% plant agar; 50 mM kanamycin;and 200 mM carbenicylin (Duchefa). The culture plates were incubated at4° C. for 48 hours then transferred to a growth room at 25° C. for anadditional week of incubation. Vital T1 Arabidopsis plants weretransferred to a fresh culture plates for another week of incubation.Following incubation the T1 plants were removed from culture plates andplanted in growth mix contained in 250 ml pots. The transgenic plantswere allowed to grow in a greenhouse to maturity.

Transformation of Cotton Tissues with Putative Cotton Promoters

The newly cloned cotton promoters could be evaluated directly in cottonplants by transforming the cloned binary vectors into cotton tissues foreither transient expression (Kim H J, Triplett BA. 2001), or stable genetransformation, by using commonly used protocols.

GUS Staining

Gus staining of arabidopsis and tomato plants was performed according toa routine protocol described elsewhere (Jefferson R A. et. al. 1987,Meissner et. al. 2000). Briefly, leaves are fixed in 90% ice coldacetone for 15-20 minutes (on ice), followed by removing acetone,rinsing tissue with the Working Solution [25 mM Sodium Phosphate (Sigma,USA) buffer pH=7, Ferricyanide (Sigma, USA) 1.25 mM, Ferrocyanide(Sigma, USA) 1.25 mM, Triton X-100 (Sigma, USA) 0.25%, EDTA (BioLab,Israel) 0.25 mM] for 15-20 minutes (repeat twice). Rinse solution isremoved, replaced with Staining solution [Working solution with5-bromo-4-chloro-3-indolyl-β-D-glucuronic acid (X-GlcA, Duchefa)solubilized in N,N-Dimethylformamide (BioLab, Israel) 1.5 mg/ml andDithiothreitol (DTT, Bio Lab) 100 mM] in dark (tubes wrapped withaluminum foil) and incubated over night at 37° C. Distaining is carriedby sinking the plant tissue in 70% ethanol and heating at 50° C. forabout 2 hours. Distaining step is repeated until the plant tissuebecomes transparent except the blue stained regions. Distained plantsare stored in 70% ethanol (BioLab, Israel) at room temperature.

Experimental Results

Table 11, hereinbelow, summarizes the information on the cotton geneclusters and their cloned and evaluated promoters used by the presentinventors.

TABLE 11 Cotton gene clusters and cloned promoters ORF- TissueExpression Expression Promoter Promoter Promoter Annotation SpecificityLevel Description Origin Length CT4 Cytochrome Fiber medium Expressed G.1400 P450 specific during all barbdanse fiber L. var S5 developmentstages CT74 Protodermal Fiber high Expressed G. 1000 factor 1 specificduring all barbdanse (PDF1), fiber L. var S5 development stages

GUS Staining on T1 Arabidopsis Plants

GUS was expressed under the regulation of CT4 and CT74, promoters in thegenetically transformed Arabidopsis plants. As shown in FIGS. 3a-3f highlevel of expression was obtained in the leafs of Arabidopsis plantsunder the control of the CT4 (FIG. 3b ) or CT74 (FIG. 3c ) promoters aswell as in the root tips under the control of the CT74 promoter (FIG. 3f).

GUS Staining on T1 Tomoato Plants

Results for tomato T1 generation are summarized in the Table 12, below.

TABLE 12 Arabidopsis - Reporter gene expression regulated by the twonovel promoters compared to 35S promoter Average Intensity Promoter LeafLeaf trichome Pore Root Root Tips CT4 0 1 3 0 0 SEQ ID NO: 848 CT74 1 25 0 5 SEQ ID NO: 851 35S 4 2 2 5 5 SEQ ID NO: 841 Table 12: Theintensity levels of expression represent an average of 4 independentsevents and are expressed by arbitrary numbers from 1 to 5, where 1 = lowexpression, and 5 = highest intensity, as was estimated by twoindependent observers. ND—not determined.

As shown in Table 12, a high level of expression is obtained under thecontrol of CT4 promoter in the pores. In addition, a high level ofexpression is obtained under the control of the CT74 promoter in theroot tips and pores, and a moderate level of expression is obtained inthe leaf trichomes.

Altogether, these results demonstrate the isolation of a set of cottonfiber specific promoters which allow expression of the candidate genesat the right time and right strength. Thus, the four new fiber specificpromoters which were identified, isolated and characterized in thepresent study exhibit different levels of expression: very high (CT74),high (CT9), moderate (CT4) and low expression (CT11). These promoterswere shown to represent different patterns of expression: initiation(CT4), elongation (CT9 and CT74) and constitutive expression (CT11).

Example 11 Agroinjection of Cotton Developed Balls—a New Tool for RapidAnalysis of Genes and Promoters Directly in Developed Fibers

In order to demonstrate fiber related gene expression, the genes shouldbe over-expressed in the relevant tissue, the ovule. To-date, atransient expression system, which uses natural grown cottonovules/fibers, does not exist. The present inventors have devised amethod of infecting cotton ovule cells using agroinjection in order todemonstrate over expression of fiber related genes on fiber development,as follows.

Briefly, the assay is based on the co-expression of a marker gene and atested gene. A green-fluorescent-protein (GFP) (SEQ ID NO:871) orGUS-intron (GUSint, SEQ ID NO:872) as a reporter gene is cloned underregulation of CT2 fiber specific promoter (SEQ ID NO:873) (disclosed inPCT Patent Appl. No IL2005/000627 to Evogene Ltd.) in cis to the testedfiber related genes CT1, 2, 3, 6, 7, 9, 11, 20, 22, 27, 40, 71, 74, 75,76, 81, 82, 84, and 4 (SEQ ID NOs:874-892) (disclosed in PCT PatentAppl. No IL2005/000627 to Evogene Ltd.) under regulation of theconstitutive CaMV 35S promoter (SEQ ID NO:841). Expression of thereporter gene pinpoints on the fibers that were successfully transformedwith the construct. Those “reporter-positive”fibers are analyzed forfiber characteristics. The binary vector backbone is pBI101.3 (Clontech,Accession No. U12640).

Experimental Procedures

I. Cloning of the Selected Genes in a Binary Vector Under ConstitutiveRegulation and in Cis to CT2promoter::GFP Recombinant Expression:

Cloning GFP into the pGI Expression Vector

For cloning the GFP gene, primers for the GFP gene were designed to spanthe full ORF from the binary vector pGFP(+ATG)+35S. Additionalrestriction endonuclease sites were added to the 5′ end of each primer(GFP_ORF_F_Sm2 and GFP_R_Sc) to facilitate further cloning of the GFP tothe binary vector (pGI). Primers used for PCR amplification were:GFP_ORF_F_Sm2: 5′-GACCCGGGAAACAATGAGTAAAGGAGAAGAAC-3′ (forward, SEQ IDNO:893); and GFP_R_Sc: 5′-TTGAGCTCTCATCAGGTTGACTTGTATAGTTCATCCATG-3′(reverse, SEQ ID NO:894).

The resultant PCR blunt ended products were purified using PCRPurification Kit (Qiagen, Germany), digested with SmallSacI restrictionendonucleases (Roche) and cloned into the pGI binary vector (FIG. 1),while replacing the existing GUSint reporter gene. pGI is a modifiedversion of pBI101.3 (Clontech, Accession No. U12640). pGI wasconstructed by inserting a synthetic poly-(A) signal sequence, whichoriginated from pGL3 Basic plasmid vector (Promega, GenBank AccessionNo. U47295, where the synthetic poly-(A) signal sequence is locatedbetween nucleotides 4658-4811), into the HindIII restriction site ofpBI101.3 (while reconstituting the HindIII site, downstream to thepoly-(A) insert), to avoid the possibility of read-through effect of theupstream Nos-promoter and replace GUS for GUSint. To replace the GUSintgene with the GFP gene in the pGI binary vector, pGI was digested withthe appropriate restriction enzymes [5′ prime restriction SmaI and 3′prime restriction enzyme SacI (Roche—using the protocol provided by themanufacturer)]. Open binary vector was purified from the gel usingNucleoTrap kit (Macherey-Nagel). 5-75 ng of a PCR product of the GFPgene and 100 ng of open pGI plasmid vector were ligated in 10 μlligation reaction volume using T4 DNA ligase enzyme (Roche), followingthe protocol provided by the manufacturer. Ligation products wereintroduced into E. coli cells. The new constructs were designatedpGFP(-35s).

Recombinant Expression in Bacteria

60 μl of E. coli, strain DH5-α competent cells (about 10⁹ cells/ml) weretransformed using 1 μl of ligation reaction mixture by electroporation,using a MicroPulser electroporator (BioRad), 0.2 cm cuvettes (BioRad)and EC-2 electroporation program (BioRad). E. coli cells were grown on 1ml LB liquid medium at 37° C. for 1 hour and 0.2 ml of the cellsuspension were plated on LB-agar plates supplemented with theantibiotics kanamycin 50 mg/L (Sigma). Plates were then incubated at 37°C. for 16 hours. Bacteria colonies were grown and expression wasconfirmed by PCR amplification using primers that were designed to spanthe inserted sequence in the binary vector. Primers used for DNAamplification of the inserts in the pGFP(-35s) binary vector were: 101F5′-GCTATGACCATGATTACGCC-3′: (forward, SEQ ID NO:869) and NOS_R:5′-GCGGGACTCTAATCATAAAAACC-3′ (reverse SEQ ID NO:895).

PCR products were separated on 1% agarose gels and product sizes wereestimated by comparing to DNA ladder (MBI Fermentas). PCR products withthe predicted size were sequenced using the same primers previously usedfor PCR amplification.

Sequencing of the inserted sequence was performed to verify that theclones were introduced in the right orientation, and to eliminate thepossibility that sequence errors were included during PCR amplification.DNA sequences were determined using ABI 377 sequencer (AmershamBiosciences Inc).

CT2 promoter sequence, originated from the pGI+CT2 promoter (PCT PatentAppl. No. IL2005/000627 to the present inventors) was cloned bydigesting the pGI+CT2 promoter vector with the restriction endonucleasesHindIII and BamHI (Roche) and ligated into the binary constructs(pGFP(-35s)), digested with the same enzymes. Ligation products wereintroduced into E. coli cells and screen for positive colonies withprimers: (forward 101F, SEQ ID NO:869) and (reverse GFP_R1,SEQ ID NO:8965′-CACCTTCACCCTCTCCACTG-3′).

pCT vectors, harboring the tested genes [CT1, 2, 3, 6, 7, 9, 11, 20, 22,27, 40, 71, 74, 75, 76, 81, 82, 84, 4, SEQ ID NOs. 874-892; (disclosedin PCT Patent Appl. No IL2005/000627 to Evogene Ltd.)] were digestedwith the restriction endonuclease HindIII (Roche) and dephosphorylatedwith Alkaline Phosphatase (shrimp; Roche). The CT2 promoter::GFP wasamplified using primer including HindIII restriction enzyme site.Primers used for PCR amplification were: CT2_pro_H:5′-TTCAAGCTTTTTTTGTTTGTTGTGGGGG-3′ (forward, SEQ ID NO:897) andNOS_ter_R_H: 5′-GGTTAAGCTTCGACGGCCAGTGAATTCC-3′ (reverse, SEQ IDNO:898).

The resultant PCR blunt ended products were purified using PCRPurification Kit (Qiagen, Germany) digested with HindIII (Roche) andcloned into each of the pCT dephosphorylation binary vectors (See FIG. 6for an exemplary vector). Ligation products were introduced into E. colicells and screen for positive colonies with primers: (forward 101F, SEQID NO:869) and 35S_R: 5′-GGACCACTGTCGGTAGAGGC-3′ (reverse, SEQ IDNO:899).

II. Cloning of the Selected Genes in a Binary Vector Under ConstitutiveRegulation and in Cis to CT2promoter::GUS Recombinant Expression:

Cloning the Tested Genes into the pGI+CT2-Promoter Expression Vector

For cloning the tested genes under regulation of 35S promoter, primersfor the 35Spromoter and NOS terminator were designed. Additional HindIII(Roche) restriction endonuclease sites were added to the 5′ end of eachprimer to facilitate further cloning of the tested genes [CT1, 2, 3, 6,7, 9, 11, 20, 22, 27, 40, 71, 74, 75, 76, 81, 82, 84, 4, SEQ IDNOs:874-892; (disclosed in PCT Patent Appl. No IL2005/000627 to EvogeneLtd.)], to the binary vector (pGI+CT2 promoter). Primers used for PCRamplification were: 5′-TTCTCTAAGCTTGCATGCCTGC-3′ (forward, SEQ IDNO:900) and 5′-GGTTAAGCTTCGACGGCCAGTGAATTCC-3′ (reverse, SEQ ID NO:901).Each of the above genes was cloned into the CT2 promoter GUSpGI+CT2-promoter (PCT Patent Appl. No. IL2005/000627). TheCT2promoter::GUS plasmid were digested using the endonucleases HindIII(Roche) and dephosphorilation with Alkaline Phosphatase, shrimp (Roche).

Ligation products (see FIG. 7 for an exemplary vector) were introducedinto E. coli cells and screen for positive colonies as describepreviously.

Agrobacterium Transformation of Binary Plasmids Harboring the Genes ofInterest and Expression in Cotton Ovules

Each of the 38 binary constructs, comprising the 35S promoter upstreamof each of the tested CTs genes and CT2 promoter::GFP or GUS wastransformed into cotton developed ovules via Agrobacterium tumefaciencetransformation.

60 μl of Agrobacterium tumefaciens C58 competent cells (about 10⁹cells/ml) were transformed with 20 ng of binary plasmid viaelectroporation, using a MicroPulser electroporator (BioRad), 0.2 cmcuvettes (BioRad) and EC-2 electroporation program (BioRad).

Agrobacterium cells were grown on 1 ml LB+50 mg/L of Carbenicillin+50mg/L of Rifampicillin liquid medium at 28° C. for 3 hours and 0.08 ml ofthe cell suspension were plated on LB-agar plates supplemented with theantibiotics 50 mg/L of Carbenicillin+50 mg/L of Rifampicillin+50 mg/L ofKanamycin Plates were then incubated at 28° C. for 72 hours.Agrobacterium colonies were grown and PCR amplification was performed onAgrobacterium cells, using primers that were designed to span theinserted sequence in the binary vector. Primers used for PCRamplification were for GUS:

pGI(CT2 promoter) + CT20(35S promoter) Forward, CT20_F_2(SEQ ID NO: 902) 5′-ACGGAGTCAACTCAGAATCG-3′; and Reverse, CT2_pro_R_2(SEQ ID NO: 903) 5′-TGCATTATTCAAACCCTGTCTCC-3′. pGI(CT2 promoter) +CT82(35S promoter) Forward, CT82_RT_F (SEQ ID NO: 904)5′-TCTCTAAGCGACGAAACGGGT-3′; and Reverse, CT2_pro_R_2. (SEQ ID NO: 903)pGI(CT2 promoter) + expansin (SEQ ID NO. 905) (35S promoter)Forward, p35s_R  (SEQ ID NO: 899) and Reverse, CT2_pro_R_2.(SEQ ID NO: 903) For the GFP construct: Forward 101F,  (SEQ ID NO: 869)and Reverse, GFP_R1 (SEQ ID NO: 896) 5′-CACCTTCACCCTCTCCACTG-3.′

PCR products were separated on 1% agarose gels and product sizes weredetermined by comparing to DNA ladder (MBI Fermentas).

Agrobacterium tumefaciens-Mediated Transient Assay for Cotton Balls

5 ml of Agrobacterium cultures (C58) were grown overnight fromindividual colonies at 28° C. in LB medium plus selective antibiotics.The next day the culture cells were recovered by centrifugation,resuspended in infiltration medium (10 mM MgCl₂, 10 mM MES, 200 μMacetosyringone, pH 5.6) to optical density=2, and incubated at roomtemperature with gentle agitation (20 rpm) for a minimum of 2 hours.Cultures were combined when required, collected with a syringe, and 300μl were injected in the cotton balls by using a needle.

Agroinjection

Cotton balls (Gossypium. hirsuturn cv Coker/DP&L90) at different stagesof development 0, 2, 4 and 6 days post anthesis (DPA) were infiltrated(with the agrobacteria harboring the binary vector) using a 1-ml syringewith a 0.5-316-mm needle (BD Pastipak). Needle was introduced 1 to 2 mmin depth into the fruit tissue, and the infiltration solution was gentlyinjected into the fruit. The total volume of solution injected variedwith the size of the fruit, with a minimum of 0.1 ml and a maximum of0.3 ml.

GUS Staining of the Cotton Ovules

Leaves were fixed in 90% ice-cold acetone for 15-20 minutes (on ice),followed by removal of acetone, the tissue was rinsed with the WorkingSolution [25 mM Sodium Phosphate (Sigma, USA) buffer pH=7, Ferricyanide(Sigma, USA) 1.25 mM, Ferrocyanide (Sigma, USA) 1.25 mM, Triton X-100(Sigma, USA) 0.25%, EDTA (BioLab, Israel) 0.25 mM] for 15-20 minutes(repeat twice). The rinse solution was removed, replaced with Stainingsolution [Working solution with5-bromo-4-chloro-3-indolyl-β-D-glucuronic acid (X-GlcA, Duchefa)solubilized in N,N-Dimethylformamide (BioLab, Israel) 1.5 mg/ml andDithiothreitol (DTT, Bio Lab) 100 mM] in dark (tubes wrapped withaluminum foil) and incubated over night at 37° C. Distaining was carriedby sinking the plant tissue in 70% ethanol and heating at 50° C. forabout 2 hours. Distaining step was repeated until the plant tissuebecame transparent except the blue stained regions. Distained plantswere stored in 70% ethanol (BioLab, Israel) at room temperature.

Experimental Results

Detection of Positive Agroinjection Using GUS

Validation of the agroinjection process was done using agroinjection ofGUS under regulation of CT2 and 35S promoters at 1 and 8 DPA. After twodays (3 and 10 DPA), the developed ball was picked and the ovules wereGUS staining (FIGS. 4a-4c ).

Analysis of Cotton Developed Fibers

First validation of the gene detection was done using agroinjection of 2DPA ovules with two constructs: 35S::CT20, CT2pro::GFP; 35S::expansin,CT2pro::GFP; After two days (4 DPA), the developed ball was picked andthe ovules were screened for fiber analysis. In order to detect thedeveloped fiber length, the present inventors have made a widthwiseslice of about 0.2 mm. The slices were screened for GFP expression underUV light using 10× microscope lens. Positive GFP were points on positiveinfiltration. The developed fiber length of the positive GFP ovules wasdetermined (in micron) using lens scale. In order to measure the effectof each of the selected gene on the fiber development, three differentagroinjection flowers were used; in each flower three different ovuleswere measured. The fiber length measurements are summarized in Table 13,hereinbelow. From the results it is possible to see that expansin (FIG.5c ) and CT20 (FIG. 5b ) exhibited an elongation effect on 4 DPAdeveloped fiber as compared to control (FIG. 5a ). Quantitation of suchan elongation effect is depicted in Table 13, hereinbelow.

TABLE 13 Influence of overexpression of new genes in 4 DPA developedfiber on fiber length Construct Fiber length 35S:: expansin, CT2pro::GFP12.5 35S::CT20, CT2pro::GFP 11.8 CT2pro::GFP 10.6

Using agroinjection the present inventors have demonstrated theinfluence of cotton genes on fiber development, and the detection ofexpression of reporter genes under the transcriptional control of cottonfiber promoters. Previous studies have shown that transgenic cottonlines overexpressing Expansin produce fiber of increased length (US Pat.Application No. US20040006794). This study shows that agroinjection ofexpansin in 4 DPA developed fiber results with an enlarged fiber lengthas compared to control. Elongation of the 4 DPA developed fiber was alsoobserved by overexpression of CT20 (SEQ ID NO:881). In previous studies,the present inventors have demonstrated the possibility to use tomatoseed hair as model for cotton fiber and showed that CT20 significantlyelongated tomato seed hair compare to wild type (0.366±0.006 mm compareto 0.319±0.008) (PCT Patent Appl. No. IL2005/000627 to the presentinventors). In this study the present inventors show, for the firsttime, that expression of fiber developing genes such as CT20 andexpansin to an already developed fibers (e.g., 2, 4 or 8 DPA) cansignificantly elongate cotton fibers.

Although the invention has been described in conjunction with specificembodiments thereof, it is evident that many alternatives, modificationsand variations will be apparent to those skilled in the art.Accordingly, it is intended to embrace all such alternatives,modifications and variations that fall within the spirit and broad scopeof the appended claims.

All publications, patents and patent applications mentioned in thisspecification are herein incorporated in their entirety by referenceinto the specification, to the same extent as if each individualpublication, patent or patent application was specifically andindividually indicated to be incorporated herein by reference. Inaddition, citation or identification of any reference in thisapplication shall not be construed as an admission that such referenceis available as prior art to the invention. To the extent that sectionheadings are used, they should not be construed as necessarily limiting.

REFERENCES Additional References Cited in Text

-   Clough S. J, and Bent A. F (1998). Floral dip: a simplified method    for Agrobacterium-mediated transformation of Arabidopsis thaliana.    Plant J. 16, 735-43.-   Curtis I. S, Davey M. R, and Power J. B. 1995. Leaf disk    transformation. Methods Mol. Biol. 44, 59-70.-   Desfeux C, Clough S. J, and Bent A. F (2000). Female reproductive    tissues are the primary target of Agrobacterium-mediated    transformation by the Arabidopsis floral-dip method. Plant Physiol.    123, 895-904.-   Goodin M M, Dietzgen R G, Schichnes D, Ruzin S, Jackson A O. pGD    vectors: versatile tools for the expression of green and red    fluorescent protein fusions in agroinfiltrated plant leaves.    Plant J. 2002 August; 31(3):375-83.-   Jefferson R A, Kavanagh T A, Bevan M W. GUS fusions:    beta-glucuronidase as a sensitive and versatile gene fusion marker    in higher plants. EMBO J. 1987 Dec. 20; 6(13):3901-7-   Kapila et al. 1997 Kapila J., de Rycke R., van Montagu M. and    Angenon G. (1977): “An “Agrobacterium”-mediated transient gene    expression system for intact leaves.” Plant Science 122, 101-108.-   Kim H. J, and Triplett B. A. 2001. Cotton fiber growth in planta and    in vitro. Models for plant cell elongation and cell wall biogenesis.    Plant Physiol. 2001 December; 127(4):1361-6.-   Meissner R, Chague V, Zhu Q, Emmanuel E, Elkind Y, Levy A. A. 2000.    Technical advance: a high throughput system for transposon tagging    and promoter trapping in tomato. Plant J. 22, 265-74.-   Orzaez D., Mirabel S., Wieland W H., Granell A. 2006; Plant    Physiology, 140: 3-11.-   Ruan Y. L, Llewellyn D. J, and Furbank R.T. 2003. Suppression of    Sucrose Synthase gene expression represses cotton fiber cell    initiation, elongation and seed development. Plant Cell 15, 952-964.-   Wagner. G. J, Wang. E and Shepherd. R. W. 2004. New approaches for    studying and exploiting an old protuberance, the plant trichome.    Ann. Bot. 93, 3-11.-   Wang E, Gan S, and Wagner G. J. 2002. Isolation and characterization    of the CYP71D16 trichome-specific promoter from Nicotiana tabacum L.    J Exp Bot. 53(376):1891-7.-   Yang Y, Li R, Qi M. In vivo analysis of plant promoters and    transcription factors by agroinfiltration of tobacco leaves.    Plant J. 2000 June; 22(6):543-51.

What is claimed is:
 1. A nucleic acid construct comprising an isolated polynucleotide comprising a nucleic acid sequence encoding a polypeptide comprising an amino acid sequence at least 99% identical to the amino acid sequence set forth by SEQ ID NO: 930 and an operably linked regulatory sequence capable of regulating expression of said polynucleotide sequence in a cell, wherein said polypeptide increases fiber length when expressed in a plant, and wherein said regulatory sequence is heterologous to said isolated polynucleotide.
 2. The nucleic acid construct of claim 1, wherein said amino acid sequence is set forth by SEQ ID NO:
 930. 3. A nucleic acid construct comprising an isolated polynucleotide comprising a nucleic acid sequence encoding a polypeptide at least 97% identical to the polypeptide set forth by SEQ ID NO: 930, wherein said nucleic acid sequence is selected from the group consisting of SEQ ID NOs: 913 and 1, and an operably linked regulatory sequence capable of regulating expression of said polynucleotide sequence in a cell, wherein said regulatory sequence is heterologous to said isolated polynucleotide, and wherein said polypeptide increases fiber length when expressed in a plant.
 4. The nucleic acid construct of claim 1, wherein said fiber comprises a cotton fiber.
 5. The nucleic acid construct of claim 1, wherein said regulatory sequence is a constitutive promoter.
 6. The nucleic acid construct of claim 1, wherein said regulatory sequence is a tissue-specific promoter.
 7. The nucleic acid construct of claim 1, wherein said regulatory sequence is an epidermal cell promoter.
 8. A transgenic cell comprising the nucleic acid construct of claim
 1. 9. A transgenic plant comprising the nucleic acid construct of claim
 1. 10. A method of generating a transgenic plant, comprising transforming a cell of a plant with the nucleic acid construct of claim 1, thereby generating the transgenic plant.
 11. A method of producing cotton fibers, the method comprising: (a) generating a transgenic cotton plant transformed with the nucleic acid construct of claim 1, and (b) harvesting the fibers of said transgenic cotton plant, thereby producing the cotton fibers.
 12. A method of increasing biomass, vigor, yield, abiotic stress tolerance and/or fiber length of a plant, the method comprising transforming the plant with a polynucleotide encoding a polypeptide comprising an amino acid sequence at least 99% identical to the amino acid sequence set forth by SEQ ID NO: 930, wherein said polynucleotide is operably linked to a heterologous regulatory sequence capable of regulating expression of said polynucleotide sequence in a cell, thereby increasing the biomass, vigor, yield, abiotic stress tolerance and/or fiber length of the plant as compared to a native plant of the same species which is grown under the same growth conditions.
 13. The method of claim 12, wherein expression of said polynucleotide is effected at a root tip of the plant.
 14. A method of increasing biomass, vigor, yield, abiotic stress tolerance and/or fiber length of a plant, the method comprising transforming the plant with a polynucleotide encoding a polypeptide comprising the amino acid sequence set forth by SEQ ID NO: 930, wherein said polynucleotide is operably linked to a heterologous regulatory sequence capable of regulating expression of said polynucleotide sequence in a cell, thereby increasing the biomass, vigor, yield, abiotic stress tolerance and/or fiber length of the plant as compared to a native plant of the same species which is grown under the same growth conditions.
 15. The nucleic acid construct of claim 1, wherein said nucleic acid sequence has a preferred codon usage for a particular plant cell.
 16. The nucleic acid construct of claim 1, wherein said nucleic acid sequence is the nucleic acid sequence set forth by SEQ ID NO: 913 or a codon optimized sequence thereof.
 17. The nucleic acid construct of claim 1, wherein said nucleic acid sequence is set forth by SEQ ID NO:
 913. 18. A transgenic cell comprising the nucleic acid construct of claim
 2. 19. A transgenic plant comprising the nucleic acid construct of claim
 2. 20. A method of generating a transgenic plant, comprising transforming a cell of a plant with the nucleic acid construct of claim 2, thereby generating the transgenic plant.
 21. The method of claim 14, wherein said nucleic acid sequence has a preferred codon usage for a particular plant cell.
 22. The method of claim 14, wherein said nucleic acid sequence is the nucleic acid sequence set forth by SEQ ID NO: 913 or a codon optimized sequence thereof.
 23. The method of claim 14, wherein said nucleic acid sequence is set forth by SEQ ID NO:
 913. 24. The method of claim 12, wherein said abiotic stress is salinity stress.
 25. The method of claim 12, wherein said abiotic stress is nutrient deficiency.
 26. The method of claim 14, wherein said abiotic stress is salinity stress.
 27. The method of claim 14, wherein said abiotic stress is nutrient deficiency. 